non-destructive techniques to investigate the …
TRANSCRIPT
Autumn School on Physics of
Advanced Materials
(PAMS-1)
Iasi 2014
book of ABSTRACTS
Organizers:
11th Carol I Blvd, 700506 Iași, Romania
Co-organizers:
RoMS-CGS
CONTENTS
Lectures
lecture
(L)
presenting
author
title page
L1 Stefan Antohe
Non-destructive techniques to
investigate the defects in thin films
11
L2 Viacheslav
Barsukov
Promising materials for Li-ion
batteries
12
L3 Shizutoshi
Ando
Preparation and characterization of
ZnS thin films by the chemical bath
deposition method
13
L4 Masaaki
Nagatsu
Low-temperature plasma processing
for biomedical applications
14
L5 Mikhail
Avdeev
Nanodiamonds in solutions: structural
aspects by small-angle neutron
scattering
15
L6 Abdullah
Yildiz
Carrier transport mechanisms in metal-
oxide thin films
16
L7 M. Kompitsas Thin film metal oxide electrochemical
gas sensors, functionalized by noble
metal nanoparticles
17
L8 Firuta Borza
Amorphous and nanocrystalline
magnetic micro- and nanowires
18
L9 Osman
Adiguzel
Crystal systems and parent-product
structure relation in shape memory
alloys
19
L10 Catalin Martin Structure and symmetry of the
superconducting gap in Fe-based
superconductors
20
L11 Peter Sloan
Atomic manipulation with the
scanning tunnelling microscope: how
to play with atoms
21
L12 Kathrin Müller
Photoelectron spectroscopy to
investigate chemical, electronic and
structural properties of surfaces
22
L13 Marco Lattuada Physicochemical properties of
nanoparticles suspensions
23
L14 Regis YN
Gengler
Hybrid functional thin films grown by
a modified Langmuir Blodgett method
24
L15 Vincenzo
Buscaglia
Engineering the phase transitions in
barium titanate: fundamental strategies
and application in multilayer ceramic
capacitors
25
L16 Alexander
Pikulin
Direct laser writing by multi-photon
polymerization: fundamentals and
theoretical concepts
26
L17 Oana Raita
What EPR tell us about the spin
dynamics in nanostructured materials?
27
L18 Isabelle
Berbezier
Morphological evolution of SiGe
layers in epitaxy on Si substrate during
MBE growth
28
Student’s posters
Poster
(Ps)
presenting
author title page
Ps1 Liliana M.
Trinca
Transparent oxides for electronic
applications
29
Ps2 Ilona Senyk, Super-pure graphite materials and
methods for their purification
30
Ps3 Olena
Ustavytska
Oxygen reduction nanocomposite
electrocatalysts based on conjugated
polymers (polyphenylenediamines,
polyindole) with cobalt
31
Ps4 R. Stanculescu The role of porosity on the functional
properties of BaSrTiO3 ceramics
32
Ps5 Olena
Tynkevych
Temperature-dependent band gap
variation in CdTe–CdS core–shell
quantum dots
33
Ps6 Claudia
Nadejde
Catalytical removal of relevant
pollutants from waters using
nanocatalysts
34
Ps7 Marcela-Corina
Rosu
Ag/TiO2 nanoparticles embedded into
pectin-allantoin-glycerol matrix as
promising UV photoprotective systems
36
Ps8 Constantin
Lefter
Charge transport phenomena in
molecular spin crossover compounds
37
Ps9 Catalin Palade Effects produced by bismuth
irradiation on high resistivity silicon
39
Ps10 Eduard
Sebastian Barca
Nanostructured powders elaboration
by spvd (solar physical vapor
deposition)
40
Ps11 Maria Andries The influence of magnetic
nanoparticles on the oxidative activity
in cellulolytic fungi
41
Ps12 Emil Puscasu Stable colloidal suspension of
magnetite nanoparticles for
applications in life sciences
42
Ps13 Geanina Laura
Pintilei
The influence of Al2O3 and TiO2
deposited coatings to the behavior of an
aluminum alloy subjected to
mechanical shock
43
Ps14 Gabriel Oanca The preparation and the
characterization of some water-based
ferrofluids
44
Ps15 Vasile-Adrian
Surdu
10 mol% YSZ ceramics and
composites synthesis, characterization
and electric properties
45
Ps16 Rozina
Steigmann
Electromagnetic investigation of
carbon fiber reinforced plastics
46
Ps17 Vlad Preutu Investigation of composites based on
Poly–ε–caprolactone and
magnetic/ferroelectric nanoparticles
47
Ps18 Carmen -
Mariana
Popescu
Morphological changes in metallic
core/polymer shell nanostructures at
the interaction with physiological
media
48
Ps19 Gigel Gicu
Nedelcu
Structural and magnetic properties of
superparamagnetic magnetite
nanoparticles superficially isolated
with biocompatible polymers
49
Ps20 Joana Lancastre The inorganic oxide network
microstructure in Si based ormosils
prepared by gamma radiation
50
Ps21 Daniel Florin
Sava
Synthesis of nanomaterials with
potential application in sensitized solar
cell
51
Ps22 Aurelian
Carlescu
Magnetoresistance behavior in
thermally treated organic spin valve
52
Ps23 Anton Smirnov The model for laser annealing of non-
linear crystals
53
Ps24 Constantin
Virlan
Photocatalytic evaluation of ferrite
nanoparticles synthesized in palm oil
54
Ps25 Stefan Ionita Structural investigation of surface and
biological properties of some
composite resins for dental
reconstruction
55
Ps26 Mihaela Toma Structural investigation of Ni- and Co-
doped ZnO thin films grown by spin
coating
56
COMMITTEES
ICPAM-10 and PAMS-1 Chairs
Felicia IACOMI - Faculty of Physics, Alexandru Ioan Cuza
University of Iasi, Romania
Valentin CRACIUN - National Institute for Laser, Plasma and
Radiation Physics, Magurele, Romania
ICPAM-10 and PAMS-1 Session Chairs
Isabelle BERBEZIER - IM2NP - CNRS, University Paul Cézanne,
Marseille, France
Valeria HARABAGIU - Petru Poni Institute for Macromolecular
Chemistry, Iasi, Romania
Nicoleta LUPU - National Institute of Research & Development
for Technical Physics, Iasi, Romania
Emmanuel KOUDOUMAS - Technological Educational Institute of
Crete, Greece.
Marco LATTUADA - Adolphe Merkle Institute, University of
Fribourg, Switzerland.
Nikita BITYURIN - Institute of Applied Physics, Russian Academy
of Sciences, Russia Nizhnii Novgorod, Russia.
Masaaki NAGATSU - Graduate School of Science and Technology,
Shizuoka University, Hamamatsu, Japan.
Kathrin MUELLER - Zernike Institute of Advanced Materials
University of Groningen, The Netherlands.
Cris ORFESCU - NanoArt 21, Los Angeles, California, US.
Viacheslav BARSUKOV - Department for Electrochemical Power
Engineering & Chemistry, Kiev National University of Technologies
and Design, Ukraine.
Mikhail AVDEEV - Joint Institute for Nuclear Research, Dubna,
Russia.
Abdullah YILDIZ - Yildirim Beyazit University, Ankara, Turkey.
Simion SIMON - Faculty of Physics, Babes - Bolyai University, Cluj-
Napoca, Romania
Stefan ANTOHE - Faculty of Physics, University of Bucharest,
Bucharest, Romania
Organizing committee
Shizutoshi ANDO – Tokio University of Science, Tokio, Japan
Aytunç ATES – Yildirim Beyazit University, Ankara, Turkey
Cristian BABAN – Alexandru Ioan Cuza University of Iași, Romania
Pascal BALDI – University of Nice Sophia Antipolis, Nice, France
Rozsa BARANYAI – Centre for Energy Research, Hungarian Academy of
Sciences, Budapest Neutron Center, Hungary
Florin BRANZA – Alexandru Ioan Cuza University of Iași, Romania
Güven ÇANKAYA – Yildirim Beyazit University, Ankara, Turkey
Dorina CREANGA – Alexandru Ioan Cuza University of Iași, Romania
Mircea CRISAN – Alexandru Ioan Cuza University of Iași, Romania
Richard CROSS – EMTERC, De Monfrot University, Leicester, UK
Aura DARIESCU – Alexandru Ioan Cuza University of Iași, Romania
Ioan DUMITRU – Alexandru Ioan Cuza University of Iași, Romania
Cristian FOCSA – Université des Sciences et Technologies de Lille, France
Paul GASNER – Alexandru Ioan Cuza University of Iași, Romania
Silviu GURLUI – Alexandru Ioan Cuza University of Iași, Romania
Fahrettin GOKTAS – Yildirim Beyazit University, Ankara, Turkey
Nickolaos KATSARAKIS – Technological Educational Institute of Crete,
Heraklion, Greece
Liviu LEONTIE – Alexandru Ioan Cuza University of Iași, Romania
Diana MARDARE – Alexandru Ioan Cuza University of Iași, Romania
Cathy PAITEL – IM2NP, Université Aix-Marseille et Sud Toulon Var,
France
Sebastian POPESCU – Alexandru Ioan Cuza University of Iași, Romania
Munizer PURICA – National Institute of Research & Development for
Microelectronics, Bucharest, Romania
George G. RUSU – Faculty of Physics, Alexandru Ioan Cuza University of
Iasi, Romania
Iulia SALAORU – Southampton Nanofabrication Centre, Faculty of
Physical Sciences and Engineering, University of Southampton, UK
Adriana SAVIN – National Institute of Research & Development for
Technical Physics, Iași, Romania
Mirela SUCHEA – Alexandru Ioan Cuza University of Iași, Romania
Daniel TAMPU – Petru Poni Institute of Macromolecular Chemistry, Iași,
Romania
Sorin TASCU – Alexandru Ioan Cuza University of Iași, Romania
Romulus TETEAN – Babes-Bolyai University, Cluj-Napoca, Romania
Lee WHEATLEY – Science Photography, Image Source UK
Advisory committee Metin AKTAS – Yildirim Beyazit University, Ankara, Turkey
Marco ABBARCHI – University Paul Cézanne, Marseille, France
Marc De MICHELI – University of Nice Sophia Antipolis, Nice, France
Christian BERNHARD – University of Fribourg, Switzerland
Mircea CHIPARA – Indiana University, Bloomington, Indiana, US
Horia CHIRIAC – National Institute of Research and Development for
Technical Physics, Iași, Romania
Ciprian DARIESCU – Alexandru Ioan Cuza University of Iași, Romania
George KIRIAKIDIS – Institute of Electronic Structure and Laser (IESL),
Foundation for Research and Technology, University of Crete, Heraklion,
Greece
Serafettin EREL – Yildirim Beyazit University, Ankara, Turkey
Chantal FONTAINE – Laboratoire d’Analise et d’Architecture des
systemes-CNRS, Toulouse, France
Violeta GEORGESCU – Alexandru Ioan Cuza University of Iași, Romania
Domenico GRIMALDI – Università degli studi della Calabria, Cosenza,
Italy
Janez GRUM – Faculty of Mechanical Engineering, University of Ljubljana,
Slovenia
Igor EVTODIEV – State University of Moldova, Chișinău, Moldova
David HUI – University of New Orleans, US
Prashant N. KUMTA – University of Pittsburg, Pittsburg, US
Dumitru LUCA – Alexandru Ioan Cuza University of Iași, Romania
Cornel MUNTEANU – Gheorghe Asachi Technical University, Iași,
Romania
Alfonso NASTRO – Università degli studi della Calabria, Cosenza, Italy
Maria NEAGU – Alexandru Ioan Cuza University of Iași, Romania
Shashi PAUL – EMTERC De Montfort University, Leicester, U.K.
Florentin PALADI – State University of Moldova, Chișinău, Moldova
Efstathios POLYCHRONIADIS – Aristotle University of Thessaloniki,
Greece
Antoine RONDA – Institut Materiaux Microelectronique Nanosciences de
Provence, Universités Aix-Marseille et Sud Toulon Var, France
Gheorghe I. RUSU – Alexandru Ioan Cuza University of Iași, Romania
Bogdan C. SIMIONESCU – Petru Poni Institute of Macromolecular
Chemistry, Iași, Romania
Alexandru STANCU – Alexandru Ioan Cuza University of Iași, Romania
Fernanda Maria Amaro MARGAÇA – Instituto Superior Técnico, Centro
de Ciências e Tecnologias Nucleares, Lisbon, Portugal
Local organizing committee
Cătălin ADOMNIȚEI – Alexandru Ioan Cuza University of Iași, Romania
Maria ANDRIES - Alexandru Ioan Cuza University of Iași, Romania
Andreea-Georgiana BULAI - Alexandru Ioan Cuza University of Iași,
Romania
Marius M. CAZACU - Alexandru Ioan Cuza University of Iași, Romania
Aurelian CARLESCU – Alexandru Ioan Cuza University of Iași, Romania
Petronela DORNEANU – Petru Poni Institute of Macromolecular
Chemistry, Iași, Romania
Dragoș DUTU - Alexandru Ioan Cuza University of Iași, Romania
Nicoleta IFTIMIE - National Institute of Research & Development for
Technical Physics, Iași, Romania
Stefan IONITA - Alexandru Ioan Cuza University of Iași, Romania
George KENANAKIS - Technological Educational Institute of Crete,
Estavromenos Iraklio Crete, Greece
Otilia LEOBA - Alexandru Ioan Cuza University of Iași, Romania
Gigel NEDELCU - Alexandru Ioan Cuza University of Iași, Romania
Valentin NICA - Alexandru Ioan Cuza University of Iași, Romania
Iosif Iulian PETRILĂ – Alexandru Ioan Cuza University of Iași, Romania
Daniela Angelica PRICOP - Alexandru Ioan Cuza University of Iași,
Romania
Emil PUȘCAȘU - Alexandru Ioan Cuza University of Iași, Romania
Alicia Petronela RAMBU - Alexandru Ioan Cuza University of Iași,
Romania
Alina SOROCEANU - Petru Poni Institute of Macromolecular Chemistry,
Iași, Romania
Cristian STELEA – Alexandru Ioan Cuza University of Iași, Romania
Mihai TOMA - Alexandru Ioan Cuza University of Iași, Romania
Florin TUDORACHE - Alexandru Ioan Cuza University of Iași, Romania
Ioana-Laura VELICU – Alexandru Ioan Cuza University of Iași, Romania
11
L1 Non-destructive techniques to investigate the defects in thin films Stefan Antohe
Electricity, Solid State and Biophysics, University of Bucharest, Faculty of Physics,
405 Atomistilor,
P. O. Box MG-11, 077125, Magurele, ILFOV, Romania
The Current-Voltage (I-V) characteristics of the Space-Charge-Limited-
Currents (SCLC), change as a function of density and distribution of the defects
into the Band-Gap (BG) of the semiconductor. Knowing the analytical
relationships of the SCLC I-V characteristics for different trap distributions,
the intrinsic and extrinsic charge carrier transport parameters could be
determined by fitting of the measured I-V characteristics with these analytical
relationships. More quantitative information on the defects present into BG of
a semiconductor can be achieved from Termo Stimulated Currents (TSC)
spectra analysis, too. As example of the application of these defect
investigation techniques, the electrical properties of the non-irradiated and
electron irradiated structures, containing polycrystalline thin layers of CdS and
CdSe, were investigated. The current-voltage characteristics, recorded at
temperatures in the range 150÷400 K, showed that the Ohm’s law is followed
at low-applied voltages, in both non-irradiated and irradiated CdS and CdSe
layers. In the range of high-applied voltages, the space-charge-limited-current
(SCLC), controlled by different types of trap distribution, placed in the band
gape of the semiconducting layer, and has been identified as the dominant
conduction mechanism. An analysis in the frame of SCLC theory allowed us
to obtain the parameters characterizing the trap distributions and the changes
induced by electron irradiation. For a better accuracy other techniques like
TSC, Photoconduction spectra were used to characterize the irradiation
induced defects. The parameters characterizing all the detected traps were
determined.
12
L2 Promising materials for Li-ion batteries Viacheslav Barsukov, Volodymyr Khomenko, Irina Makyeyeva
Electrochemical Power Engineering & Chemistry, Kyiv National University of
Technologies and Design, Kiev, Ukraine
The more popular negative active material for lithium-ion batteries (LIBs) is
usually flake graphite due to its excellent cycle life and low price. The main
disadvantage of graphite is a relatively low specific capacity limited by the
theoretical value Q = 372 mA×h/g. Si, Sn, Al, and some other materials are the
alternate materials for LIBs. However, they have not received a practical
application, since their large theoretical capacity is accompanied by sharp drop
of capacity during the first few cycles. We have formulated the theoretical
principles [1, 2] and developed some experimental composite anode materials,
which give possibility to reach a high level of capacity (ca 600 mA×h/g) during
the stable cyclization. Our team has an experience in synthesis and
characterization of positive composite carbon materials, based on the mixed
oxides, as well as Fe phosphate. These materials can ensure quite high specific
capacity, safety and acceptable price for LIBs. Different new types of
electrolytes, polymer binders and separator materials also have been analyzed.
We have developed a new lithium-ion battery technology that is more powerful
than existent for comparable batteries. The improvement of lithium-ion
batteries have been achieved due to advantage of the electrode specifications
and novel nano-materials.
[1] V. Khomenko, V. Barsukov, J. Doninger, I. Barsukov, J. Power Sources, 165/2 (2007) 598-
608.
[2] V. Khomenko, V. Barsukov, Electrochimica Acta, 52, No 8 (2007) 2829-2840.
13
L3 Preparation and characterization of ZnS thin films by the chemical
bath deposition method Shizutoshi Ando
Department of Electrical Engineering, Faculty of Engineering, Tokyo University of
Science,
6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
Type II-VI semiconductors have long been developed as materials for
optoelectronics. Recently, type II-VI semiconductors have also been employed
in the buffer layer of Cu(In,Ga)Se2 (CIGS) thin-film solar cells. The chemical
bath deposition (CBD) method is one of the growth of thin film by wet process.
Furthermore, this method is a simple apparatus for the deposition of thin film,
and the equipment used has a lower cost compared with sputtering, and vacuum
evaporation which are dry process used for a mass production line. In recent
years, extensive research has been conducted on CIGS-based thin film solar
cells. These thin film solar cells have achieved conversion efficiencies
exceeding 20%, with many using CdS thin films prepared by CBD. However,
CdS thin films contain Cd, which has a large impact on the environment.
Research has therefore been conducted on using ZnS thin films as the buffer
layer in these thin film solar cells with the aim of further increasing efficiency
while improving environmental friendliness. CIGS-based thin film solar cells
that use a ZnS thin film prepared by CBD (CBD-ZnS) have achieved
conversion efficiencies of over 18% [2]. It is anticipated that the conversion
efficiencies of these thin film solar cells will be increased by improving the
crystallinity of the CBD-ZnS thin films. In this study we investigated three
types of temperature profile processes with regard to the CBD deposition
method and trial-manufactured CBD-ZnS thin film with good crystallinity. In
addition, we aimed to establish conditions for deposition. Improved
crystallinity was therefore expected by annealing of CBD-ZnS thin films
fabricated using this thin film growth method, and the effectiveness and
annealing parameters were investigated. ZnSO4 and ZnI2 were used as Zn
source materials and thiourea [SC(NH2)2] was used as the sulfur source
material. In addition, aqueous ammonia (NH4OH) was used as the complexing
agent, with pure water used as the solvent. Quartz (SiO2) and SnO2/glass plate
were used as the substrate for growing the films.
[1] Miguel A. Contreras, K. Ramanathan, J. AbuShama, F. Hasoon, D.L. Young, B. Egaas and
R. Noufi, Proc. Photovolt. 13 (2005) 209.
[2] T. Nakada and M. Mizutani, Jpn. J. Appl. Phys. 41 (2002) L165.
14
L4 Low-temperature plasma processing for biomedical applications Masaaki Nagatsu
Nanovision Science Section, Shizuoka University Graduate School of Science and
Technology , Hamamatsu, Japan
In this talk, recent experimental results on plasma surface functionalization
of nano-structured materials for biomedical applications are presented. The
main objectives are; (1) to fabricate nano-structured materials by various
plasma processing, (2) to modify their surfaces by plasma chemical
modification, and (3) to immobilize the desired materials onto the surface of
nano-structured materials for biomedical application. In order to achieve the
objectives described above, graphite-encapsulated magnetic nanoparticles,
vertically aligned carbon nanotube dot-arrays (for a biochip sensor) and ZnO
nanoparticles (as fluorescent materials) were used to investigate the low
temperature plasma processing. With the graphite-encapsulated magnetic
nanoparticles, we studied the plasma processing by using the two-step plasma
treatment, Ar plasma pre-treatment followed by NH3 plasma post- treatment,
to introduce the functional groups onto the surface of the nanoparticles. With
conventional chemical procedures, the amino group population of magnetic
nanoparticles having a typical diameter of 20 nm was evaluated to be about 8
x 104 molecules per nanoparticle. Immobilization of the antibody of influenza
virus onto the surface of aminated magnetic nanoparticles has been carried out
for aiming at developing the feasibility of the collection and condensation of
virus. We observed a significant enhancement of collection rate of the
influenza virus using the antibody-immobilized magnetic nanoparticles. The
present result suggests the feasibility of the magnetic condensation method for
rapid detection of influenza virus. This surface modification processing was
also utilized in the case of the ZnO nanoparticles as a fluorescent material for
bioimaging application. As the second topic, the selective ultrafine surface
modification of functional groups onto the polymeric substrate or vertically
aligned CNT dot-array with a dot size of 5 μm and 50 μm spacing was
investigated using the atmospheric pressure plasma jet with a nano/micro-sized
capillary. The micro-sized surface modification of amino or carboxyl groups
introduced onto the substrate were confirmed by the fluorescence labelling
technique.
15
L5 Nanodiamonds in solutions: structural aspects by small-angle
neutron scattering Mikhail Avdeev
Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna,
Russia
Detonation nanodiamond (DND) particles attract increasing attention as a
promising nanomaterial due to its biocompatility, ability to penetrate the cell
membrane, and easy functionalization and conjugation with biomolecules. The
synthesis of stable in time and concentrated aqueous dispersions of DND
shows a significant progress in recent years. The presence of liquid
homogeneous media in such systems makes it possible to apply rather
effectively the small-angle neutron scattering (SANS) to clarify some
important structural aspects of the inner particle structure and particle
interaction. SANS experiments from DND solutions (concentration range of 1-
10%) from different producers reveal a strong effect of aggregation. The large
aggregates (mean size above 120 nm) are characterized by a developed
organization with fractal dimension D ~ 2.3-2.5, thus pointing out a common
mechanism of a diffusion limited cluster–cluster aggregation. They can
interpenetrate each other when concentrating the system, which determines a
gel transition in the systems. Small clusters are compact and interact by the
‘hard-sphere repulsion’ mechanism. The particles composing the aggregates
(DND particles) show a complex inner structure corresponding to a rather wide
spatial diamond-graphite transition within the particles (in terms of averaged
radial density profile). This transition is reflected in the formation of the
diffusive interface on the particle surface, which can be well described using
the data of SANS contrast variation experiments. In addition to the
characteristics of the transition, the parameters of the DND particle size
distribution function are obtained.
[1] M. V. Avdeev, et al., J. Phys. Chem. C 113 (2009) 94,
[2] M. V. Avdeev, et al., J. Phys. Cond. Matter 25 (2013) 445001
[3] O. V. Tomchuk, et al., J. Appl. Cryst. 47 (2014) 642
16
L6 Carrier transport mechanisms in metal-oxide thin films Abdullah Yildiz
Faculty of Engineering and Natural Sciences, Yıldırım Beyazıt University, Ankara,
Turkey
Recently, there have been several attempts to understand the outstanding
electrical transport properties of metal oxide films. The analysis of carrier
transport properties of these materials is always difficult and controversial.
There are several models explaining carrier transport behavior of metal oxide
films. These models are simple thermal activation process (Arrhenius law),
single phonon-assisted Mott type variable-range hopping (Mott-VRH), single
phonon-assisted Efros-Shklovskii type variable-range hopping (ES VRH),
adiabatic small polaron hopping (A-SPH), non-adiabatic small polaron
hopping (N-SPH), multiphonon hopping (MPH), thermionic emission (TE)
and tunneling (TN) grain boundaries (GBs) conductions, Meyer-Neldel Rule
(MNR), metallic conduction (MC), electron-electron interactions (EEI), weak
localization (WL) and anti-weak localization (AWL) models. Depending on
some parameters such as the employed temperature range, Bohr radius, band
gap, crystal structure, and degrees of disorder in the investigated film, one can
expect that one or more than one of these models hold. A clear transition from
a conduction mechanism to another may be also observed. This study reviews
and evaluates the carrier transport mechanisms of various metal-oxide
materials such as ZnO, SnO2, TiO2, In2O3, and CuO.
17
L7 Thin film metal oxide electrochemical gas sensors, functionalized
by noble metal nanoparticles M. Kompitsas1, M. Kandyla1, P. Koralli1,2, G. Mousdis1
1National Hellenic Research Foundation, Theoretical and Physical Chemistry
Institute, Athens,
48 Vasileos Constantinou Avenue, 11635 Athens, GREECE 2School of Mechanical Engineering, National Technical University of Athens, Athens,
Iroon Polytechniou 9 Zografos, 15780 Athens, GREECE
Electrochemical gas sensors are those that their conductivity changes, when
they react with a gas. Today, semiconducting metal oxide (SC-MO) thin films
form a special class of gas sensors that are portable, cheap, consume low power
and are characterized by high sensitivity and stability. Most of the sensor
developments concerned n-type MO films and thus they mainly occupy the
market today. Less p-type SC-MO films are known (NiO, CuxO, CoO), and
show generally less gas sensitivity. During the last 10 years, intensive work
has started on p-type gas sensors development. Various growth techniques
have been applied, such as sol-gel, sputtering, spray pyrolysis, pulsed laser
deposition (PLD) a.o. To account for the low sensitivity, noble metal
nanoparticles (Au, Pd, Pt) have been either embedded into the film matrix
during growth or used to partially cover the film surface in a post growth
process. Independent of the type of growth and functionalization, such MO-
noble metal nano-compounds have shown increased sensitivity and faster
response, when tested against hydrogen/air mixtures, down to a few ppm and
at low temperatures. Currently, sensing characteristics are optimized by
controlling the concentration of the noble metal in the compound. The
efficiency of a gas sensor is given by the so-called 3S criterion: Stability-
Sensitivity-Selectivity. In particular selectivity is a critical aspect if a sensor is
surveying a complex gas environment. Such problems are solved by using
sensor arrays that are educated by neural networks to respond only to one gas
type. The simplest array may consist of two sensors. For example, an n-type
(ZnO) and a p-type (NiO) thin film sensor, when tested against the reducing
hydrogen gas, show an increase and decrease of the conductivity, respectively.
Thus, oxidizing and reducing gases can be easily distinguished.
18
L8 Amorphous and nanocrystalline magnetic micro- and nanowires Firuta Borza
Magnetic Materials and Devices, National Institute of Research & Development for
Technical Physics, Iasi, Romania
Amorphous magnetic wires have been available for more than two decades
and research on these materials has been established in many laboratories
throughout the world. The group in the National Institute of Technical Physics,
Iasi has performed pioneering work in the preparation and characterisation of
wire-shaped amorphous and nanocrystalline materials since 1990s in both “in
rotating water quenched” and “rapid drawing from the melt in glass coating”
wire systems with typical diameters ranging from hundreds to several
micrometers. Recently, the technological limits of the glass-coated melt
spinning method were pushed beyond those used for the production of glass-
coated microwires and thus, the diameters of microwires has been drastically
reduced down to hundreds of nanometers. Due to combined strong directional
physical properties, unique magnetoelastic interactions, magnetic structure,
and specific interphase interactions magnetic wires exhibit a diverse range of
physical effects (large Barkhausen discontinuity, fast domain-wall (DW)
propagation, and giant magnetoimpedance (GMI) at MHz frequencies). The
current interest in microwires includes: (i) the opportunity of processing novel
wire systems of various compositions and geometry, (ii) basic studies on
micromagnetics of the magnetization reversal process (particularly in wires
with a single domain wall) and its dynamics, (iii) high-frequency studies on
GMI and ferromagnetic resonance, showing quite interesting properties at
MHz and GHz frequencies, and (iv) technological applications mostly as
sensing elements in various devices and recently in smart materials. There are
two main magnetic features of microwires that make them attractive for
applications namely, their bistable behavior and their magnetoimpedance
response, but other interesting applications are based on the magnetoelastic
effect and stress-impedance effects. The unique properties and cost effective
preparation process of glass-coated amorphous nanowires makes them good
candidates in spintronics applications. Acknowledgements- Work supported by the Romanian Ministry of National Education,
under project SMARTFLOW (Theme PN-II-PT-PCCA-2013-4-0471).
19
L9 Crystal systems and parent-product structure relation in shape
memory alloys Osman Adiguzel
Department of Physics, Firat University, Elazig, Turkey
Crystals are characterized by regular arrangement of atoms or molecules and
consist of periodic arrangements of atoms, and each repeating unit is the unit
cell. Each unit cell has a geometric structure, and different lattice systems are
created by varying the lattice parameters; a, b and c, and the angles, a, b and g.
Considering the geometric structures, seven crystal systems are obtained, and
all the seven lattice systems have a total of 14 crystal structures. Directions are
defined in real space, and crystal planes are described with Miller indices in
reciprocal space. In the determination of crystal structure, x- ray and electron
diffractions are mainly used. Diffraction is an action of the interference of the
diffracted rays from the parallel crystal planes. The systematic rules of x-ray
diffraction are Bragg’s Law and structure factor, F(hkl). Alloys are composed
of two or more types of elements, and have different phases, depending on the
alloy composition. Heat treatment is important factor in the formation of stable
and metastable phases, and the change in the microstructure is called phase
transition or phase transformation. A series of alloy systems exhibit a peculiar
property called shape memory effect based on a solid state phase
transformation, martensitic transformation. Martensitic transformations are
first order phase transformations and occur with cooperative movement of
atoms by means of lattice invariant shears in materials on cooling from high
temperature parent phase region. Experimental studies were performed on two
ternary copper based alloys; CuZnAl and CuAlMn. Simulation studies were
performed on a molecular dynamics cell (MDC) of NiAl alloy model using
molecular dynamics (MD) simulation technique. Two molecular dynamics
(MD) simulation methods which allow the system to vary in shape and size
was used. For this purpose, square molecular dynamics cells (MDC) of 216 B2
unit cells which include 432 atoms have been constructed. The molecular
dynamics cell (MDC) has been cooled and heated in a temperature interval,
700K-350K. Sutton-Chen and Lennard-Jones potential energy functions have
been adopted to explain how the potential energy functions affect the
transformation mechanism.
J. MA. I. Karaman and RD. Noebe, International Materials Reviews 55, 257, 2010.
O. Adiguzel, Journal of Materials Processing Technology 185, 120, 2007.
S. Ozgen, O. Adiguzel, J. Physics and Chemistry of Solids 65,861, 2004.
20
L10 Structure and symmetry of the superconducting gap in Fe-based
superconductors Catalin Martin1, V. G. Kogan2, M. Tanatar2, N. Ni2, A. Diaconu3, L. Spinu3, D. B.
Tanner4, P. C. Canfield2, R. Prozorov2 1Engineering Physics, Ramapo College of NJ, Mahwah, USA
2Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, USA 3Advanced Materials Research Institute, University of New Orleans, New Orleans, USA
4Physics, University of Florida, Gainesville, USA
The recent discovery of superconductivity in iron arsenide compounds, with the highest
critical temperature exceeding Tc = 50 K, has reignited the interest in the field. Advance
in crystal growth techniques, characterization tools and computational methods have
allowed the exploration of these new superconductors at an almost unprecedented rate.
Several related classes of materials were synthesized within less than one year and their
electronic properties were determined both theoretically (via band structure calculations)
and experimentally, almost at the same time. Despite all these rapid developments,
fundamental questions, like the mechanism for pairing, or the structure and symmetry of
the superconducting gap, are still debated today. In this lecture, I will give an overview of
Fe-based superconductors and discuss the evolution of our understanding of the pairing
mechanism and of the structure of the superconducting gap. A detailed study of high
sensitivity penetration depth experiments will be presented and discussed, in connection
with other experimental methods and with theoretical predictions. I will make the case
that the superconducting gap is highly anisotropic, and even nodal, in many of these
compounds. Additionally, optical conductivity data will be involved, arguing for possible
electronic inhomogeneity in some of the Fe-based compounds, which affects experimental
measurements and complicates the understanding of the superconducting properties in
these materials.
C. Martin et al., Phys. Rev. B, 81 060505(R) (2010)
C. Martin et al., Supercond. Sci. Technol., 23, 065022 (2010)
C. Martin et al., Phys. Rev. Lett., 102, 247002 (2009)
21
L11 Atomic manipulation with the scanning tunnelling microscope:
how to play with atoms Peter Sloan
Department of Physics, University of Bath, Bath, UK
The ultimate building blocks of matter are atoms and molecules. If we can
control these we can truly build from the bottom up, for example, a computer
made of atomic-scale components that would fit into the palm of your hand,
yet would be more powerful than today's supercomputers. In 1986 the Nobel
prize was won for the scanning tunneling microscope (STM) which can image
individual atoms. In 1989 this microscope was used to assemble, atom-by-
atom, the world’s first ever atomically precise structure (a tiny advert for IBM).
So why, in the intervening 23 years, has such atomic scale engineering not
become commonplace in modern technology? In this talk I will review what
can be done at the single molecule level, for example, breaking or making
individual chemical bonds, adding a single electron to a single gold atom,
constructing a molecular transistor, constructing molecular logic gates. All
these are beautiful examples of the power of single molecule science, but are
strictly one-atom-at-a-time methods of construction. This leads to a
fundamental manufacturing bottleneck with resulting lengthy and tedious
construction of anything but the simplest structure. I conclude by showing a
possible solution where we extend the control of the microscope from one atom
to many.
22
L12 Photoelectron spectroscopy to investigate chemical, electronic and
structural properties of surfaces Kathrin Müller
Zernike Institute for Advanced Materials, University of Groningen, Groningen, The
Netherlands
Photoelectron spectroscopy (PES) is one of the most versatile techniques
to study surfaces and interfaces due to its high surface sensitivity and
flexibility. In this lecture I will review several different PES techniques like x-
ray photoelectron spectroscopy (XPS), angle-resolved photoelectron
spectroscopy (ARPES) and normal incidence x-ray standing waves (NIXSW).
XPS is one of the most often used techniques to investigate chemical
composition of surfaces and interfaces, because it is specific to the elemental
and chemical composition and it can be used to quantify the surface
composition. While for XPS core-hole electrons are analyzed ARPES is used
to measure valence electrons. Thus, it is specific to the occupied electronic
bands and can be used to get a map of the electronic band structure in the
reciprocal space. NIXSW uses the constructive or destructive interference of
the incoming and outgoing high energy photons the distance of adsorbates with
respect to the surface can be mapped. Besides explaining the experimental set-
ups and basic physical principles I will also show several illustrative examples
on how these techniques are used in modern surface science in order to
characterize surface properties.
23
L13 Physicochemical properties of nanoparticles suspensions Marco Lattuada
University of Fribourg, Adolphe Merkle Institute, Marly, Switzerland
Many nanoparticles, independently of their preparation, need to be
dispersed in suitable solvents. The so-obtained colloidal dispersions have many
unique properties, mostly a consequence of the particles small size and high
specific surface. In this lecture, the most important physicochemical properties
of dispersions will be reviewed. These include the typical mechanisms
responsible for particles dispersion, i.e., Brownian motion, and shear forces.
Then the concept of colloidal stability will be addressed. Since colloidal
stability is an essential feature of colloidal dispersions, the main interparticle
forces involved in determining particles stability will be reviewed. These
include Van der Waals forces, electrostatic interactions and steric forces. The
fate of unstable colloidal suspensions and aggregation kinetics will also be
addressed.
24
L14 Hybrid functional thin films grown by a modified Langmuir
Blodgett method Regis YN Gengler
Zernike Institute For Advanced Materials, University of Groningen, Groningen, The
Netherlands
This tutorial will report on a new method based on the use of Langmuir-
Schaefer deposition for the creation of functional nano-materials. The
fundamental principle of this simple, but yet powerful method will be
explained. Successful examples of the use of this hybrid method for the
creation of high electronic quality reduced graphene oxide and exfoliated
graphene films will be presented. Examples of the combination of the
aforementioned method with self-assembly will also be shown. That
combination allowed the creation of hybrid organic-inorganic nanostructures
for magnetism: insert of highly anisotropic Ni(8) magnetic molecules, creation
of Prussian Blue analogues of reduced dimensionality and other photo-
switchable magnetic materials. Various example of successful deposition and
creation of functional nanostructured materials will be presented supported by
spectroscopic, crystallographic, and magnetic data. The described method is
thought as a new route toward the highly controlled fabrication of tailored
functional organic-inorganic nanomaterials.
25
L15 Engineering the phase transitions in barium titanate: fundamental
strategies and application in multilayer ceramic capacitors Vincenzo Buscaglia
Institute for Energetics and Interphases, National Research Council, Genoa, Italy
The discovery of BaTiO3 after World War II has transformed piezoelectric
and ferroelectric effects from just a scientific curiosity to a highly innovative
and profitable industry with applications in underwater sonars, medical
imaging, diesel engine injection systems and non-volatile memories. Owing to
the high dielectric constant (of the order 2000-4000) and the low losses (tan
delta about 1%), BaTiO3–based ceramics have also found application as
dielectrics in multilayer ceramic capacitors (MLCCs), the most widely used
passive electronic component in consumer electronics and cars. A MLCC is
basically composed of a stack of dielectric layers separated by metallic
electrodes where the single thin plate capacitors are connected in parallel. The
dielectric layers are fabricated by tape casting of ceramic slurries, a robust and
cheap technology. Despite more than 50 years of evolution, the MLCC
technology is still progressing. The main market trend is towards
miniaturization and the need to achieve higher capacitance in a smaller volume.
Nowadays the top end capacitors can have more than 1000 layers and a
dielectric thickness of 0.5 micron. This means that the lateral dimension of a
typical MLCC is no more than 1 mm. Main requirement for MLCCs is a flat
dielectric constant over a typical temperature range of -50 to 150°C. Pure
BaTiO3 ceramics are not suitable for this application because of the strong
permittivity variations at the Curie temperature (125°C) and around room
temperature (orthorhombic/tetragonal transition). Therefore, in order to exploit
the excellent dielectric properties of the material, the influence of doping,
formation of solid-solutions, non-uniform dopant distribution and grain size
were extensively investigated. As a result, the permittivity peaks corresponding
to the phase transitions could be shifted, broadened and even suppressed while
maintaining a high dielectric constant (>1000), and many formulations evolved
in commercial products. In this lecture, a general overview on the engineering
of the phase transitions in BaTiO3 ceramics and on the development of the
MLCC technology will be given.
26
L16 Direct laser writing by multi-photon polymerization: fundamentals
and theoretical concepts Alexander Pikulin
Nonlinear Dynamics and Optics, Institute of Applied Physics, Russian Academy of
Sciences, Nizhniy Novgorod, Russia
Multiphoton polymerization is a unique rapid prototyping technique that
allows for submicron spatial resolution in three dimensions. The polymer
micro- and nanostructures can be created by direct writing by a focused beam
of the ultrashort-pulse laser. This lecture will focus mostly on the
fundamentals and the modeling aspect of laser nanopolymerization. Initially,
an overview of the direct laser writing (DLW) technique will be given.
Monte Carlo realizations of polymer voxels
The most up-to-date achievements in this field will be outlined. The goal of
the lecture is to address the peculiarities of the nanoscale polymerization and
discuss the physical mechanisms that determine the spatial resolution and
minimal feature size that can be achieved with DLW.
27
L17 What EPR tell us about the spin dynamics in nanostructured
materials? Oana Raita
Physics of Nanostructured Materials , National Institute for Research and
Development of Isotopic and Molecular Technologies , Cluj-Napoca, Romania
EPR (FMR) spectroscopy is a very sensitive technique to investigate the
incorporation degree of TM ions, detection of the ferromagnetic ordering and
spin dynamics as function of the annealing temperature, dopant concentration
in different advanced materials. The main goal of this work is to investigate by
EPR the effects of: (i) partial substitution with diamagnetic ions at Mn site (ii)
grain size reduction on the exchange coupling integral between Mn spins, J,
and the polaron activation energy, Ea in substituted microstructured and
nanosized manganites, respectively. Also, I will present EPR (FMR)
investigations of Zn(1-x)TM(x)O and Sn(1−x)TM(x)O(2) micro and nano
powders (TM= Mn, Co, Fe) which reveal information about the presence of the
ferromagnetic phase inferred from the shift of the magnetic field position of
EPR line to the lower field and the line broadening as the temperature is
lowered; Evidence of both isolated TM ions located substitutionally at Zn (Sn)
sites and interstitial ones situated on the particle surfaces; The spin dynamic
properties of the samples as evidenced by EPR are very sensitive to the
annealing temperature; The ferromagnetism in Zn(1-x)TM(x)O and
Sn(1−x)TM(x)O(2) appears only in the low-temperature annealed samples.
28
L18 Morphological evolution of SiGe layers in epitaxy on Si substrate
during MBE growth Isabelle Berbezier
IM2NP, CNRS, AMU, Marseille, France
The aim of this lecture is to review the different phenomena observed
during the epitaxy on Silicon starting from the basic concepts (reconstruction,
step edge energy, equilibrium shape, surface energy anisotropy) to describe the
growth modes and regimes as a function of the experimental conditions
(temperature, flux, stress, crystalline orientation). I will also present the
different growth instabilities and discuss their kinetic, thermodynamic or
energetic origin. As an example, the quantitative study of step bunching
instability during the epitaxy of Si/Si(001) vicinal substrates, the
morphological evolution of Si layers and their modeling by kinetic Monte
Carlo simulations will be described. These studies did show the importance of
surface diffusion anisotropy on the atomic steps mobility on Si. The
microscopic origin of this kinetic instability is explained by the different
sticking barriers at the SA and SB steps i.e. in fine by the presence of a pseudo-
inverse Schwoebel barrier. In a second part, the morphological evolution of
epitaxial layers under compressive biaxial stress will be exposed. A particular
attention will be paid to the low strain regime during which the formation of
3D islands by the interrupted coarsening of the Asarro Tiller Grinfeld (ATG)
instability. The compliant effect of specific pseudo-substrates (SOI or porous
silicon in different experimental conditions) on this evolution will be
mentioned. The demonstration of a counter-intuitive effect discovered by
continuum theory modelling (J.N. Aqua) showing the enhanced development
of the instability on a softer substrate will be explained.
29
Ps1 Transparent oxides for electronic applications Liliana M. Trinca1,2, Aurelian C. Galca1, Cristina F. Chirila1, Cristina
Besleaga1, Andra G. Boni1,2, Lucian Pintilie1 1Multifunctional Materials and Structures, National Institute of Materials Physics,
Magurele, Romania 2Condensed Matter Physics, Faculty of Physics, University of Bucharest, Magurele,
Romania
Due to growing needs of the modern human, transparent electronics become
an emerging science and technology field focusing on processing and
developing invisible circuits. There is a global trend to minimize the cost of the
final product-electronic device, starting from raw materials to adaptability on
the currently existing platforms. Zinc oxide (ZnO), a transparent material,
gains a huge interest due to low price and to the possibility to tune the optical
and electrical properties by slightly impurifying. Doping ZnO with Aluminum
(AZO), the semiconductor to metal transition can be achieved (free electrons
concentration of ~ 1020 cm-3) [1]. Short time p-type is achieved by doping ZnO
with Lithium (LZO) [2]; it was also reported that LZO thin films are
ferroelectric [3]. In this work, the technological process of achieving ZnO-
based thin films and multilayer structures starting from raw powders is
presented. Aiming the fabrication of thin film transistors, each layer has been
thoroughly investigated: AZO as transparent electrode and LZO as gate
dielectric (or even ferroelectric). X-ray diffraction, Spectroscopic Ellipsometry
and electrical measurements indicate the proper recipe, and also give a
comprehensive chart which interlinks the physical properties of the thin
films/multilayers.
[1] A. C. Gâlcă et al, Thin Solid Films 518 (2010) 4603.
[2] Sh. Yu et al, Thin Solid Films 540 (2013) 146.
[3] Dhananjay et al, J. Appl. Phys. 101 (2007) 104104.
30
Ps2 Super-pure graphite materials and methods for their purification Ilona Senyk, Volodymyr Lysin, Volodymyr Khomenko, Viacheslav
Barsukov Electrochemical Power Engineering and Chemistry, Kiev National University of
Technologies and Design (KNUTD), Kyiv, Ukraine
Super-pure graphite materials have founded a wide application for lithium-
ion batteries, fuel cells, artificial diamond production and some other key fields
of advanced materials. A row for such material is usually graphite ore, which
contains usually from 5% to 22% of natural graphite. After thorough
pretreatment including multistage flotation process it is possible to reach
intermediate product with carbon content of 95-98%, which is not sufficient
for the high-tech applications. Among the other 2-5% there are usually many
of Fe, Si, Al, Ca, Cu, Ni, Zn, Cr, Mo, W, V and other undesirable admixtures.
There are in essence two main technologies for final purification of graphite:
thermal and chemical. Thermally purified graphite has usually high purity
levels of 99.95-99.98%C, but is very costly due to the high temperatures for
treatment (ca 3000 °C), inert atmosphere (N2 or Ar2) and quite complicated
equipment (furnaces with counter flow). Chemically upgraded natural graphite
is usually available in the low purity levels, but has relatively low costs. Thus,
each route provides own advantages and disadvantages. KNUTD team has
developed few improved chemical purification processes, which give
possibility to reach the high purity level up to 99.98 %C [1]. A strategy of
chemical purification depends strongly on chemical composition and
morphology of graphite after the flotation process. If there are no sufficient
amount of Si and Al, it is possible to use acidic treatment of natural graphite in
1 stage. If there are many Si and Al, it is necessary to use 3 stage acidic-
alkaline-acidic treatments, or use different combinations of concentrated acids
in 1-2 stages.
1. Chemical method of graphite treatment, Ukrainian patents No 96846 (12.12.2011, Bul. # 23)
and No 98691 (11.06.2012, Bul. # 11).
31
Ps3 Oxygen reduction nanocomposite electrocatalysts based on
conjugated polymers (polyphenylenediamines, polyindole) with
cobalt Olena Ustavytska, Denys Mazur, Yaroslav Kurys
Department of free radicals, L. V. Pysarzhevsky Institute of Physical Chemistry of
National Academy of Sciences of Ukraine, Kyiv, Ukraine
There are two most promising types of non-precious-metal oxygen reduction
reaction (ORR) electrocatalysts based on nitrogen-contaiting conjugated
polymers (CPs): unpyrolyzed carbon-supported metal-polymer ORR
electrocatalysts based on CPs and cobalt as well as so called Me-N-C catalysts
that can be prepared by pyrolysis of CPs (as nitrogen-containing precursors),
different salts of transition metals (Co, Fe, or a combination thereon) and
carbon component. But only polypyrrole (PPy) or polyaniline (PANI) as a
components of such electrocatalysts were reported in literature. We obtained
unpyrolized metal-polymer nanocomposite electrocatalysts based on amino-
substituted analogues of PANI (poly-o-phenylenediamine – PoPDA, poly-m-
phenylenediamine – PmPDA) or structural analogue of PPy (polyindole – PIn),
cobalt, and carbon black, as well as pyrolyzed Co-N-C catalysts based on the
same CPs. Composition, morphology, structure and electrochemical properties
of prepared electrocatalysts were characterized. It is shown, that such
electrocatalysts are capable of exhibiting sufficiently high activity for the ORR
in acidic electrolyte. For example, the activity for ORR of unpyrolized
nanocomposites based on PoPDA or PmPDA (ORR onset potential, Eonset up
to 450 mV; ORR peak potential, Ep up to 245 mV vs. SHE) are markedly higher
than that for previously reported similar PANI-based composite, which may be
due to effective formation and/or increasing of the number of C/CoNx-sites in
electrocatalysts at the expense of the presence of additional nitrogen atoms in
poly(phenylenediamines). It is established that heat treatment of the
nanocomposites leads to a significant anodic shift of Eonset and Ep values. In
particular, pyrolyzed nanocomposite electrocatalysts based on PIn
characterized by Eonset ~ 600 mV and Ep ~ 445 mV (vs. SHE).
32
Ps4 The role of porosity on the functional properties of BaSrTiO3
ceramics R. Stanculescu1, C. E. Ciomaga1, C. Galassi2, L. Mitoseriu1
1Faculty of Physics, Alexandru Ioan Cuza University, Iasi, Romania 2ISTEC-CNR, Via Granarolo, no.64, I - 48018, Faenza, Italy
The purpose of this study was to prepare and to discuss the role of porosity
on functional properties in Ba0.70Sr0.30TiO3 (BST) ceramics with different
degrees of porosity. Powders with this composition were prepared following
the mixed oxide method by solid-state reaction at 950°C calcination
temperature for 4h and the bulk ceramics at 1450°C sintering temperature for
2h. Various porosities of the BST ceramic samples have been obtained by
adding lamellar carbon black in concentration of 10, 20 and 35 vol% as
sacrificial template in the BST powder. The sacrificial template burns out
during the sintering process and this induces modification in the morphology,
microstructure and pore density of the ceramic product. The purity phase of the
obtained BST ceramic was checked by XRD analysis and the microstructures
was observed using Scanning Electron Microscopy (SEM). A fracture mode
transformation from intragranular to an intergranular fracture has been
observed. Modifications of the grain size and of the grain boundaries volume
were also observed and discussed. The density of the investigated samples,
measured by Archimedes method, varies from values around 95% until 68%
of their theoretical value for the dense and porous ceramics. The effect of
addition of carbon black as pore forming agent on the dielectric response at
low and high electric field was investigated and discussed. Using Impedance
Spectroscopy method in the temperature range of (21-200)°C and frequency of
20Hz–2MHz it was observed the dielectric behavior in the BST dense and
porous ceramics. The experimental results have shown that the dielectric
permittivity of the BST ceramics with different degree of porosity decrease
with increasing the porosity, from around ~ 7500 down to ~ 250, and present a
phase transition from ferroelectric to paraelectric state for a Curie temperature
close to the room temperature (around 30°C).
Acknowledgements: This work was financially supported by CNCS-UEFISCDI project PNII-
RU-TE-2012-3-0150 and by the strategic grant POSDRU/159/1.5/S/137750, Project “Doctoral
and Postdoctoral programs support for increased competitiveness in Exact Sciences research”.
33
Ps5 Temperature-dependent band gap variation in CdTe–CdS core–
shell quantum dots Olena Tynkevych1, Natalia Vyhnan1, Konstyantyn Likhnitski2, Ilona Senyk2,
Viacheslav Barsukov2, Petro Fochuk1, Yuriy Khalavka1 1Department of Inorganic Chemistry of Solid State & Nanomaterials, Yuriy
Fedkovych Chernivtsi National University, Chernivtsi, Ukraine 22Department of Electrochemical Power Engineering & Chemistry, Kiev National
University of Technologies and Design, Kiev, Ukraine
Colloidal semiconductor quantum dots (QDs) have unique size-
dependent chemical and physical properties. Сyclic voltammetry (CV)
measurements of QDs give information about the valence and conduction
bands (from the oxidation/reduction potential values). In this study the
electrochemical band structure of CdTe–CdS core–shell QDs of different
diameter was measured. Also, we investigated the temperature-dependent
optical (ΔEopt) and electrochemical (ΔEcv) band gap variation in CdTe–CdS
core–shell QDs of different diameter stabilized by thioglycolic acid.
Measurements were carried out in the range starting from 293 K to 238 K. PL
spectra were excited by solid-state diode laser (405 nm) and recorded on a
OceanOptics USB-2000 spectrophotometer. Three-electrode system with
platinum or carbon counter electrodes, an Ag/AgCl reference electrode and the
flat platinum electrode as the working electrode was used for the CV
measurements. Scan rate were 0.2, 0.5 and 1 V/s. It was found that distance
between the oxidation and reduction peaks increases with decrease of QDs size.
This trend is consistent with spectroscopic data. However, it should be noted
that the CV band gap energy (ΔEcv) is 0.1 – 0.3 eV smaller than the optical
(ΔEopt) in most cases. A reason for these disagreements may be related to the
oxidation of surface defects forming surface states in the band gap that act as
local trap states. Investigating the temperature-dependent band gap energy
variation (ΔEopt and ΔEcv) shows that the temperature coefficient decreases
with increasing size of the QDs. The temperature dependence of the
electrochemical and optical energy gaps agree well with Varshni equation. This publication is based on the work supported by a grant from the U.S Civilian Research &
Development Foundation (CRDF Global) (UKC2-7071-CH–12), State Agency on Science,
Innovation and Informatization of Ukraine (М/85-2014), and State Fund of Fundamental
Research.
34
Ps6 Catalytical removal of relevant pollutants from waters using
nanocatalysts Claudia Nadejde1, Mariana Neamtu1, R. J. Schneider2, D. V. Hodoroaba2
1Interdisciplinary Research Department – Field Science, Alexandru Ioan Cuza
University, Iasi, Romania 2BAM Federal Institute for Materials Research and Testing , Unter den Eichen 87,
12205 Berlin, Germany
Synthetic reactive dyes are non-biodegradable major sources of water pollution
leading to severe effects on living organisms. In the last years, magnetic
nanostructures based on iron oxides were often the materials of choice in
environmental clean-up technologies [1,2] due to their availability, low cost
and environmentally friendly nature, especially when their surface is modified
with photoactive non-toxic compounds, resulting in highly efficient materials
able to remove recalcitrant organic pollutants from various media. This study
evaluates the catalytic efficiency of a novel magnetically responsive catalyst
for the degradation of two reactive azo dyes, Reactive Yellow 84 (RY84, 25
mg∙L-1) and Reactive Black 5 (RB5, 12.5 mg∙L-1) using hydrogen peroxide,
as an oxidant, under very mild conditions (atmospheric pressure and room
temperature). The catalysts were prepared by the co-precipitation method,
followed by their complexation with ferrous oxalate (FeC₂O₄∙2H₂O) in order
to enhance the overall magnetic properties of the nanomaterial. The sensitized
nanomaterial was characterized by several microstructure characterization
techniques (X-ray diffraction, vibrating sample magnetometry, scanning
electron microscopy, energy dispersive X-ray spectroscopy). All experiments
were performed on a laboratory scale set-up. Important variables such as effect
of hydrogen peroxide concentration, the amount of catalyst and contact time
for the catalytic wet peroxide oxidation (CWHPO) of RY84 and RB5 were
examined. The best experimental conditions can be described as pH = 6, T =
25 0C, a catalyst concentration of 10 g/L and 20 mmol/L H2O2. The results
show that it is possible to remove 53% in the absence of H2O2 and up to 99.7
% in the presence of 20 mM hydrogen peroxide after the 240 minutes of
oxidation at the above-mentioned conditions. Catalytic wet peroxide oxidation
on sensitized magnetic fluid of reactive dyes can be a suitable pre-treatment
method for complete decolorization of effluents from textile dyeing and
finishing processes, once the optimum operating conditions are established.
Acknowledgement: This work was supported by the CNCS–UEFISCDI through the
national grant type PN-II-ID-PCE-2012-4-0477.
35
1. Xu P., Zeng G.Mi., Huang D.L., Feng C.L., Hu S., Zhao M.H., Lai C., Wei Z., Huang
C., Xie G.X., Liu Z.F., Sci. Total Environ., 2012, 424,1.
2. Vijayaraghavan J., Sardhar Basha S. J., Jegan J.,J. Urban Environ. Eng., 2013, 7, 30.
36
Ps7 Ag/TiO2 nanoparticles embedded into pectin-allantoin-glycerol
matrix as promising UV photoprotective systems Marcela-Corina Rosu1, Lidia Magerusan2, Cristian Tudoran3
1Isotopic Physics and Technology, National Institute for Research and Development
of Isotopic and Molecular Technologies, Cluj-Napoca, Romania 2Physics of Nanostructured Systems, National Institute for Research and
Development of Isotopic and Molecular Technologies, Cluj-Napoca, Romania 3Molecular and Biomolecular Physics, National Institute for Research and
Development of Isotopic and Molecular Technologies, Cluj-Napoca, Romania
Ag-doped TiO2 nanoparticles show enhanced photocatalytic and
antimicrobial activities and they are involved in various UV photoprotection,
self-cleaning, biomedical, textile or water treatment applications [1]. Pectin is
a carbohydrate polymer with biodegradable and jellifying properties that is
often used as therapeutic and drug delivery agent [2]. Allantoin, a product of
purine metabolism, is a natural anti-irritant, soothing, skin protecting and
repairing agent by stimulating cell proliferation and rapid skin cells
regeneration [3]. Ag-doped TiO2 nanoparticles embedded into pectin-allantoin-
glycerin matrix were prepared as film-systems. The films were characterized
by mean of X-ray diffraction, FTIR and UV-VIS spectrophotometry in order
to determine the morpho-structural and optical characteristics. XRD patterns
revealed a crystalline/amorphous structure of the film-systems and the FTIR
analysis indicated the presence of inorganic component into the polymer-based
matrix. The optical transmissions of the films are influenced by the amount of
Ag-doped TiO2 nanoparticles and the addition of silver doping. The results
showed that the obtained films have suitable physical characteristics for
practical photoprotection applications. The present study could provide a basis
for further optimization of the prepared materials as photoprotective systems
with high efficiency.
[1] B. Yu, K.M. Leung, Q. Guo, W.M. Lau, J. Yang, Nanotechnology 22 (2011) 1-9.
[2] R.K. Mishra, A.K. Banthia, A.B.A. Majeed, Asian J Pharm Clin Res, 5 (2012) 1-7.
[3] M.Y. Lee, N.H. Lee, D. Jung, J.A. Lee, C.S. Seo, H. Lee, J.H. Ki
37
Ps8 Charge transport phenomena in molecular spin crossover
compounds Constantin Lefter1,2, Simon Tricard1, Haonan Peng1, Gabor Molnar1, Lionel
Salmon1, Philippe Demont3, Aurelian Rotaru2, Azzedine Bousseksou1 1LCC, CNRS, Toulouse, France
2Faculty of Electrical Engineering and Computer Science & Advanced Materials and
Nanotechnology Laboratory (AMNOL), Stefan cel Mare University, Suceava,
Romania 3LPP-CIRIMAT, CNRS, Toulouse, France
Spin-crossover (SCO) complexes of 3d4 – 3d7 transition metal ions are
paradigmatic examples of molecular materials showing bistability in
magnetic, optical and electrical properties. The high spin (HS) – low spin (LS)
transition can be triggered by various external stimuli, such as temperature,
light illumination, pressure or magnetic field. Another aspect of great interest
is the possibility of synthesizing these compounds in a variety of shapes and
sizes, ranging from large crystals, micro/nano rods to thin films or patterned
films. The versatility of these materials combined with the wide range of
operating temperatures makes them attractive for molecular nanoelectronic
and spintronic devices like molecular switches, sensor, displays and data
storage devices. [1-3].
In this work we focus on the [Fe(Htrz)2(trz)](BF4) (Htrz = 1H-1,2,4-triazole)
family.
38
Fig.1 SCO compound structure and thermal dependence of the real part of conductivity.
We investigate the possibility of organizing micro-rods between interdigitated
gold electrodes and their DC characterization. The most important
achievement of our work is that we managed, for the first time, to switch the
compound from HS state to LS state using an external electric field. This opens
new perspectives in using this class of materials in nanoelectronic devices.
Also we analyzed the effect of shape and metal dilution on AC parameters like
conductivity, permittivity and electrical modulus, providing spectacular
findings. By using spherical nanoparticles and high aspect ratio micro-rods,
we observed a shape anisotropy effect, and by diluting the complex with Zn(II)
ions we determined that the Fe(II) center plays an essential role in the polaron
hopping conduction mechanism.
[1] P. Guetlich, et al. , Beilstein Journal of Organic Chemistry, 2013, 9, 342-391.
[2] G. Molnar, et al. , Journal of Materials Chemistry C, 2014, 2, 1360-1366.
[3] A. Rotaru, et al., Advanced Materials, 2013, 25, 1745-1749.
39
Ps9 Effects produced by bismuth irradiation on high resistivity silicon Catalin Palade, Adrian Slav, Sorina Lazanu, Magdalena Lidia Ciurea
Laboratory of Nanoscale Condensed Matter Physics, National Institute of Materials
Physics, Magurele, Romania
In this work, the defects produced in Si single crystals of 8000 Ωcm
resistivity by irradiation with Bi6+ ions of 28 MeV kinetic energy having
fluence of 5x1011 ions/cm2 are investigated. By penetrating the Si crystal, the
Bi ions totally lose their energy mainly interacting with the lattice, and generate
primary defects, i.e. vacancy-interstitial pairs. These defects produce complex
point defects, some of them acting as traps, and Bi ions finally stop. The
stopped Bi ions produce a strain field into the Si host lattice as they are bigger
and heavier than Si atoms. We investigate the trapping phenomena under the
stress field by measuring and modeling the thermally stimulated currents
without bias. We charged the traps illuminating the samples with
monochromatic light of 1000, 800 and 400 nm wavelength at low temperature
and recorded the discharge currents during quasistatic heating. The trapped
carriers produce an internal electric field which is superposed on the electric
field which we modeled the strain. The detrapped carriers move under this total
electrical field. We resolved the discharge currents by modeling into seven
traps. All traps parameters were determined. We show that almost all the trap
parameters depend on the strain field.
40
Ps10 Nanostructured powders elaboration by spvd (solar physical vapor
deposition) Vasile Rizea1, Marioara Abrudeanu1, Corneliu Munteanu2, Adriana-Gabriela
Plaiasu 1, Gabriel Neacsu1, Bogdan Istrate2, Eduard Sebastian Barca1 1Engineering Science, Pitesti University, Faculty of Mechanics and Technology,
Pitesti, Romania 2Engineering Science, “Gheorghe Asachi” Technical University of Iasi, Faculty of
Mechanical Engineering, Iasi, Romania
In the recent years the demand for nanopowders are increased drastically
because of its wide range of applications. The nanotechnology offers
opportunities in creating new features and functions. Several methods are
available for the production of nanopowders production. The objective of this
paper is to offer an introduction to the fundamentals of nanotechnology and
nanopowder production using solar energy. Solar energy as a renewable energy
is one of the sources that remain to be exploited in the future. In order to
achieve the above-mentioned goals, literature research has been the starting
point. The basic principle involved in the production of nanopowders consists
in using a solar reactor to produce nanostructured powders under sun energy
starting from commercial micropowdres. The nanostructured powders are
collected on a nanostructured ceramic filter under air or inert gas pressure. All
the synthesized powders were characterized by XRD and SEM observation in
order to obtain information about crystallographic and morphology data strictly
in correspondence with solar flux and pressure in solar reactor.
41
Ps11 The influence of magnetic nanoparticles on the oxidative activity in
cellulolytic fungi Maria Andries, Lacramioara Oprica, Emilia Creanga
1 Faculty of Physics, Alexandru Ioan Cuza University, Iasi, Romania 2 Faculty of Biology, Alexandru Ioan Cuza University, Iasi, Romania
Magnetic nanoparticles (MNPs) have extensive applications in biomedicine
and biotechnology [1-3] which raise important environmental issues. Study
was carried out to assess oxidative activity induced by MNPs in fungi
microorganisms, suggesting the need to elucidate the molecular and cellular
bases of MNPs toxicity. We present the results of cellulolytic fungi response
to core/shell magnetic systems supplied in their culture medium. The enzymes
indicating oxidative stress level were assayed in fungi mycelium at seven and
fourteen days after inoculation. The increase of malondialdehyde (MDA) level
– the final product of lipid peroxidation was evidenced. Dose-response for
catalase activity was revealed between MNPs concentration and MNPS
concentration while no correlated variations have resulted for measurements of
peroxidase activity. We could conclude that the main toxic product was the
hydrogen peroxide, because of reactive oxygen species released following the
MNPs influence.
1. Prasa G L, Biomedical Applications of Nanoparticles, T.J. Webster (ed.), Safety of
Nanoparticles, Nanostructure Science and Technology -2009- P. 89-110.
42
Ps12 Stable colloidal suspension of magnetite nanoparticles for
applications in life sciences Emil Puscasu, Claudia Nadejde, Emilia Dorina Creanga
Faculty of Physics, ”Alexandru Ioan Cuza” University, Iasi, Romania
Various utilizations of magnetite nanoparticles, highly biocompatible, in
biomedicine and environmental sciences requires not only fine granulated
powder but also stable dispersion in aqueous media. Fe3O4 grains were
synthesized by chemical coprecipitation route using an adaptation of Massart’s
method [1]. The ferrophase was yield from ferric and ferrous iron salts
solutions mixed at relatively high temperature in alkali medium being further
stabilized in deionized water by coating with perchloric acid in order to prevent
the agglomeration and precipitation. Granularity of colloidal magnetite was
analyzed using SEM, crystalline properties were evidenced by XRD while
superparamagnetic characteristic, magnetic core size and saturation
magnetization by VSM investigation were assessed. The results are similar to
the literature, proving that magnetite nanoparticles coated with perchloric acid
obtained using our method could be useful in biological applications or
environment remediation.
[1]. Massart R., Preparation of aqueous magnetic liquids in alkaline and acidic media. IEEE
Transactions on Magnetics, Mag-17, 2, (1981) , pp. 1247-1248.
43
Ps13 The influence of Al2O3 and TiO2 deposited coatings to the behavior
of an aluminum alloy subjected to mechanical shock Geanina Laura Pintilei1, Marioara Abrudeanu1, Corneliu Munteanu2, Cristian
Petrescu1, Dorin Luca3, Vasile Ionut Crismaru2 1Engineering Science, Pitesti University, Faculty of Mechanics and Technology,
Pitesti, Romania 2Engineering Science, “Gheorghe Asachi” Technical University of Iasi, Faculty of
Mechanical Engineering, Iasi, Romania 3Department of technologies and equipments for materials processing, “Gheorghe
Asachi” Technical University of Iasi, Faculty of Materials Science and Engineering ,
Iasi, Romania
Aluminum alloys are used in the aerospace industry due to their good
mechanical properties and their low density compared with the one of steels.
Usually the parts made of aluminum alloys contribute to the structural frame
of aircrafts and they must withstand static and variable mechanical loads and
also mechanical loads applied in a very short time which determine different
phenomenon’s in the material behavior then static or fatigue loads. This paper
analysis the resilience of a 7075 aluminum alloy subjected to shock loads and
the way how a coating can improve its behavior. For improving the behavior
two coatings were considered: Al2O3 with 99.5% purity and TiO2. The coatings
were deposited on the base material by plasma spraying and electrochemical
deposition. The samples with and without coating were subject to mechanical
shock to determine the resilience of the materials and the cracks propagation
was investigated using SEM analysis. To highlight the physical phenomenon’s
that appear in the samples during the mechanical shock, explicit finite element
analysis were done using Ansys 14.5 software.
44
Ps14 The preparation and the characterization of some water-based
ferrofluids Gabriel Oanca1, Claudia Nadejde1, Florin Brinza1, Laura Ursu2
1Faculty of Physics, “Alexandru Ioan Cuza” University, Iasi, Romania 2Instrumental Analyses and Scientific Imaging Department, “Petru Poni”
Macromolecular Chemistry Institute, Iasi, Romania
Magnetite and oleic acid are known as developing the strongest core-shell
interactions so that the resulted colloidal systems are the most stable in liquid
suspensions. Sodium oleate is the best hydro soluble substitute of oleic acid
being also known for its biocompatibility [1]. We have prepared water-based
ferrofluids with magnetite/sodium oleate as ferrophase in two different variants
(basic and acidic) of classical method of ferric and ferrous ions coprecipitation.
Comparative analysis of the two ferrofluids was accomplished by applying
NTA (nanoparticle tracking analysis) and DLS (dynamic light scattering),
while ferrophase crystallinity was investigated by XRD (X-ray diffraction).
NTA and DLS results revealed relatively narrow size distributions of the
nanoparticles with hydrodynamic diameters no higher than 110 nm. Also, from
NTA recordings, the concentration of the magnetic nanoparticles in both
samples was determined (around 1013 particles/ml). The XRD data confirmed
the presence of magnetite crystallites with typical spinel structure in both
samples and allowed crystallites size estimation. According to DLS
measurements, high Zeta potential was found for both colloidal suspensions: -
61.04 mV for the first sample, prepared in basic medium, and -64.97 mV for
the second sample synthesized in acidic conditions; the obtained values
confirmed the good stability of both ferrofluids against dipole-dipole attraction
forces. Moreover, it was found that the second sample exhibits a lower
polydispersity index (0.655) than the first one (0.974). Real time tracking of
ferrophase grains by NTA evidenced however rare aggregates of colloidal
particles for both variants of preparation protocol. The next stage of our
research work will be focused on such aggregates frequency limitation by
improved monitoring of secondary reaction products accompanying ferrophase
yielding.
[1] Sun J., Zhou S., Hou P., Yang Y., Weng J., Li X., Li M., Synthesis and characterization of
biocompatible Fe3O4 nanoparticles, Journal of Biomedical Materials Research Part A, 80(2),
(2007), pp. 333-341.
45
Ps15 10 mol% YSZ ceramics and composites synthesis, characterization
and electric properties Vasile-Adrian Surdu1, Bogdan Ștefan Vasile1, Ecaterina Andronescu1,
Cristina Daniela Ghițulică1, Roxana Trșucă2, Cristian Hornoiu3 1Department of Science and Engineering of Oxide Materials and Nanomaterials,
University Politehnica of Bucharest, Bucharest, Romania 2METAV R and D, Bucharest, Romania
3"Ilie Murgulescu" Institute of Physical Chemistry, Bucharest, Romania
Fully yttria stabilized zirconia is one of the most attractive zirconia based
ceramics for various applications and it is used in various fields, especially as
electrolyte for SOFCs, due to its good chemical and electrical properties. The
aim of the present study was to investigate the influence of the synthesis route
and sintering method of 10 mol% YSZ ceramic and 10 mol%YSZ with 5 wt%
Al2O3 composites and to determine the effect of Al2O3 addition on its electric
properties.
10 mol% YSZ and YSZ – 5wt% Al2O3 composite nanopowders were
prepared through modified-Pechini method. The composites were prepared by
two routes: the first one involves in situ synthesis of and the second one was
carried out by adding the obtained YSZ powder in the alumina precursor
solution. The obtained powders were densified using classic and spark plasma
sintering methods.
The nanopowders and ceramics were characterized using X-Ray diffraction,
Scanning Electron Microscopy, High Resolution Transmission Electron
Microscopy and Impedance Spectroscopy at high temperature. The measured
total conductivity shows that the addition of Al2O3 with SPS sintering
technique induces a higher conductivity.
46
Ps16 Electromagnetic investigation of carbon fiber reinforced plastics Rozina Steigmann1,2, Adriana Savin1, Felicia Iacomi2
1Nondestructive Testing, National Institute of Research and Development for
Technical Physics, Iasi, Romania 2Faculty of Physics, Alexandru Ioan Cuza University, Iasi, Romania
Carbon Fiber Reinforced Plastics (CFRP) are multilayered composite
materials with applications among most different from aeronautic industry to
sport goods. The principals factors that recommend the use of CFRP are low
density, high elastic modulus along the carbon fibers direction, high ultimate
strength along the same direction, did not present fatigue phenomena and the
expansion coefficient is small. The disadvantages of these materials are low
strength at impact even at low energies (1-10J) that can lead to delaminations
with and without fiber breaking, matrix deterioration due to chemical action of
adsorbed water, the impossibility to use it at temperature over glass transition
temperature [1]. CFRP is a paramagnetic composite (μ_r=1), having electrical
conductivity relatively high in the fibers plan, 102-104 S/m [2]. Plate from
CFRP laminas with thickness of 1.91 mm, made from Polyphenylenesulphide
(PPS) reinforced with carbon fibers. The plates were impacted with energies
between 1J and 10J with an impactor with semi-spherical bumper head with
22.5mm mm diameter. For the detection of delaminations, a send –receiver
transducer was used, the reception coil being concentric with the emission one
and was diaphragmed with a circular aperture having the diameter of hole
0.25mm. The transducer is connected to the 4395A- Agilent USA. The
transducer scans a surface of 60x60mm^2 with 0.25mm steps on both
directions. The scanning is assured by an X-Y motorized stage Newmark USA.
The command of 4395A is made through IEEE488.2 Keitley interface and the
displacing system through RS 232 interface by means of a program developed
in Matlab 2011ba. The data delivered by the transducer are stored as amplitude
and phase information. The presence of circular aperture and the extremely
small lift-off (0.1mm) allow that the post-processing of the obtained signals
shall be made using Fourier optics methods [3].
This work was supported by the strategic grant POSDRU/159/1.5/S/137750, Project
“Doctoral and Postdoctoral programs support for increased competitiveness in Exact Sciences
research” cofinanced by the European Social Found within the Sectorial Operational Program
Human Resources Development 2007 – 2013
1. P. Morgan, Carbon fibers and their composite, CRC Press, Taylor & Francis, Boca Raton, 2005.
2. R. Grimberg, SC. Wooh, A. Savin, R. Steigmann, D. Premel, INSIGHT, 44, (5), pp.289-293, 2002.
3. M. Born, Principles of Optics, 1959.
47
Ps17 Investigation of composites based on Poly–ε–caprolactone and
magnetic/ferroelectric nanoparticles Vlad Preutu, Roxana Stanculescu, Mirela Airimioaei, Liliana Mitoseriu
Physics Department, Alexandru Ioan Cuza University of Iasi, Iasi, Romania
Poly–ε–caprolactone (PCL) is a biocompatible, biodegradable and
bioresorbable polymer with many interesting physicochemical properties: drug
permeability, non-toxicity, slow degradation, and low melting point. Thus PCL
may have medical applications, such as medical devices, drug delivery and
tissue engineering [1].
According to the literature, the PCL/ferrites composites can be employed in
bioengineering and medical fields: nanoparticle as magnetite encapsulated in
PCL microcapsules could be used for bone replacement or as shape–memory
composites in biomedicine, while the CoFe2O4/PCL core–shell has a great
potential for magnetic fluid hyperthermia in cancer treatment [2].
In this work, the investigation of properties of PCL–based composites filled
with magnetic (CoFe2O4) or ferroelectric (BaTiO3) nanoparticles are reported.
The composites formation and their characteristic as structure and
microstructure were investigated by XRD and SEM analyses. For all the
samples, the frequency dependence of dielectric properties at room temperature
have been investigated and discussed in correlation with the microstructural
data.
The magnetic properties of PCL/CoFe2O4 composites determined with a
vibrating sample magnetometer (VSM) show a reduction of magnetization
when decreasing the ferrite amount.
Acknowledgements: The support of PNII-PT-PCCA-2013-4-1119 MECOMAP
grant is acknowledged.
[1] M. A. Woodruff, D.W. Hutmacher, Progress in Polymer Science 35 (2010) 1217–1256.
[2] X. Yu, S. Zhou, X. Zheng, T. Guo, Y. Xiao, B. Song, Nanotechnology, 20 (2009) 235702.
48
Ps18 Morphological changes in metallic core/polymer shell
nanostructures at the interaction with physiological media Daniela - Angelica Pricop1, Lucian Hritcu2, Carmen - Mariana Popescu1
1Physics Department, "Alexandru Ioan Cuza" University, Iasi, Romania 2Biology Department, "Alexandru Ioan Cuza" University, Iasi, Romania
Gold nanoparticles were synthesized in high molecular weight chitosan matrix
by co-precipitation chemical route. Previous in vivo studies reported no
morphological changes occurred in rats brain tissue after administration of
such capped gold nanoparticles. In this paper we focused on size distribution
analysis of nanoparticles in the areas where they were localized in comparison
to their dimensional distribution in colloidal suspension. Microscopy
investigation in dark field technique revealed that nanoparticles from brain
tissue appeared to have changed size.
Fig.1 GNPs in rats brain
To understand the factors that caused the decrease of nanoparticles
dimensions, we proceed to the simulation of physiological conditions i.e. basic
pH environments similar to that of hydrocephalus medium. The main result
evidenced that extremely basic medium significantly modified the polymer
coating and its configuration around the metallic core.
1.Sathish kumar K., Madhusudhanan J., Thanigaivel, Robin A., Veni V. Biofunctionalized
nanoparticle for drug delivery,Research Journal of Biotechnology, 2013,8,70-77.
49
Ps19 Structural and magnetic properties of superparamagnetic
magnetite nanoparticles superficially isolated with biocompatible
polymers Gigel Gicu Nedelcu1, Mihail Liviu Craus2, Felicia Iacomi1
1Physics Department, "Alexandru Ioan Cuza" University, Iasi, Romania 2Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna, Russia
Magnetite nanoparticles superficially isolated with polymers have been
synthesized by co-precipitation method using ferrous and ferric salts, with the
addition of an alkaline solution of NaOH and three polymer solutions of
polyethylene glycol, polyvinyl alcohol or a polysaccharide, such as dextran.
The scanning electron microscopy and X-ray diffractometry measurement
show that particle size are in the range of 10-12 nm and have a spherical shape.
The hysteresis cycles of bare magnetite nanoparticles (a) and for those coated with dextran (b),
polyethylene glycol (c) and polyvinyl alcohol (d).
Vibrating sample magnetometry analysis has provided details on
superparamagnetic behavior of the magnetite nanoparticles. The study about
interaction between individually coated magnetite nanoparticles offer clues on
fact that nanoparticles are not agglomerates.
[1] R. Sharma, A. Sharma, C.J. Chen, Open Nanomed. J. 3 (2011) 10-23.
[2]S. Laurent, S. Dutz, U.O. Häfeli, M. Mahmoudi, Adv. Coll. Int. Sci. 166 (2011) 8–23.
50
Ps20 The inorganic oxide network microstructure in Si based ormosils
prepared by gamma radiation Joana Lancastre1, António Falcão1, Fernanda Margaça1, Luís Ferreira1, Isabel
Miranda Salvado2, M. Helena Casimiro3, Álmásy Laszlo4, Anikó Meiszterics5 1C2TN, Instituto Superior Técnico, Universidade de Lisboa , Bobadela, LRS,
Portugal 2CICECO & Departamento de Engenharia de Materiais e Cerâmica, Universidade
de Aveiro, Aveiro, Portugal 3REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e
Tecnologia, FCT, Universidade Nova de Lisboa, Caparica, Portugal 4Wigner Research Centre for Physics, Institute for Solid State Physics and Optics,
Budapest, Hungary 5Gedeon Richter LTD, Gedeon Richter LTD, Budapest, Hungary
Ormosils are organic-inorganic materials that have been the object of
intense research due to their wide range of properties and inumerous
applications. We have prepared hybrid materials of this type by gamma
irradiation of mixtures of the precursors, tetraethyl orthosilicate,
polydimethylsiloxane silanol terminated and zirconium propoxide, without
addition of any other component. Several variables have been found to
influence the microstructure of the final material. This work presents the effect
of the two parameters that were found to be the most relevant. A batch of
samples was prepared varying the polymer molecular weight while keeping the
same wt% composition of all precursors. Another batch of samples was
produced with fixed molecular weight and polymer content but changing the
Zr propoxide content. All samples were dried in air at room temperature and
then characterized by Small Angle Neutron Scattering and Scanning Electron
Microscopy among other techniques. The results shed light on the development
of the inorganic oxide network from a preparation mixture devoid of water and
on the role played by those determinant variables. A model is proposed for the
microstructure of the materials so prepared.
51
Ps21 Synthesis of nanomaterials with potential application in sensitized
solar cell Daniel Florin Sava, Anton Ficai, Bogdan Stefan Vasile, Georgeta Voicu, Ecaterina
Andronescu
Science and Engineering of Oxide Materials and Nanomaterials, Politehnica
University of Bucharest, Faculty of Applied Chemistry and Material Science,
Bucharest, Romania
Nanostructured semiconductors have a lot of applications in different fields
from electronics to medicine. One important application of these materials is
sensitized solar cells, which “threaten” to become the best solar cell type
regarding the W/$ ratio. Sensitized semiconductors became of interest for many
scientists only from 1972 but they really took scale in 1991 when Gratzel et al.
thought of using nanostructured semiconductors for constructing the solar cells
and the efficiency made a big jump to 8%. [1] This type of solar cells have
known another big step in 2006 when Kojima et al. used a hybrid perovskite
structure as a sensitizer for the solar cell.[2] Currently the highest efficiency
for sensitized solar cells is 19,3% obtained with the hybrid perovskite
structure.[3] We present in this work the synthesis of two important
nanomaterials that could be used together as a composite in constructing a low
cost dye sensitized solar cell, specifically the photoanode. The synthesized
materials are the anatase form of TiO2 with a cubic morphology that it is done
through a simple hydrothermal method while and graphene oxide which is
synthesized through a modified Hummer method. Graphene oxide could also
be used to replace the counterelectrode in the solar cell, but both materials have
the purpose of increasing the charge transport inside the photoanode. The
obtained materials were characterized through several methods: XRD, SEM,
TEM, IR spectroscopy and BET adsorption/desorption isotherms. From the
results we see the importance of controlling very well the synthesis parameters
and their effect on the properties of the obtained materials.
1. Oregan, B., M. Gratzelș; Nature, 1991. 353(6346): p. 737-740.
2. Kojima, A., Teshima, K., Shirai, Y., Miyasaka, T., in 210th ECS Meeting2006: Cancun,
Mexico.
3. Service, R.F., Science, 2014, 344(6183): p. 458.
52
Ps22 Magnetoresistance behavior in thermally treated organic spin
valve Aurelian Carlescu1, Felicia Iacomi1, Christian Bernhard2
1Physics Faculty, "Alexandru Ioan Cuza" University of Iasi, Iasi, Romania 2Physics Department, University of Fribourg, Fribourg, Switzerland
Organic Spintronics has been considered to be the physics and applications
of spin polarized electron injection, transport, manipulation and detection in
organic diodes by the application of an external magnetic field. We build an
organic spin-valve (OSV), which is based on an organic semiconductor spacer
placed in between two ferromagnetic electrodes having different coercive
fields, of which magnetoresistance changes with the applied field. Epitaxial
La0.875MnO3Sr0.125 (LSMO) thin films were grown by pulsed laser
deposition; the organic spacer Alq3 and the top ferromagnetic electrode Co
were deposited using thermal evaporation method in vacuum. The films
thickness was determined with X-ray reflectrometry (XRR) and the simulations
of the XRR data have been performed using the software package GenX.
Magnetoresistance measurements were performed using the four-point probe
option of a physical properties measurement system (PPMS) from Quantum
Design (Model QD6000). This device was heated in vacuum to various
annealing temperatures starting from 423 K to 453 K in steps of 10 K and for
a duration of 12 hours each, in order to observe the evolution of the
magneteresistance. Key-words: valve spin, spintronics, organic semiconductor,
magnetoresistance, thermal deposition.
53
Ps23 The model for laser annealing of non-linear crystals Anton Smirnov1, Nikita Bityurin
Laboratory of laser nanomodification of materials , Institute of Applied Physics of the
Russian Academy of Sciences, Nizhny Novgorod, Russia
The applicability of high-power laser pulses is limited by the stability of
the optical element. For the nanosecond pulses the threshold of the optical
damage of the transparent non-linear crystals used for laser frequency
conversion is determines by the laser heating of light-absorbing inclusions.
One of the methods of improving crystal’s quality is the sub-threshold laser
annealing. To our knowledge the mechanisms of this process have not been
properly understood. We suggest a simple model that concerns diffusion
mechanism of the laser annealing. Laser heating of the cluster of the absorbing
defects leads to activation of the diffusion of the defects decreasing thereby
their number density. Since the temperature rise is proportional to absorbing
centers concentration, the threshold of destruction becomes higher.
In order to develop this idea we have formulated theoretical problem. It is
based on the diffusion equation for the number density of the absorbing centers
with temperature dependent diffusion coefficient, and the heat diffusion
equation for the temperature distribution within the sample. The dynamics of
the defect’s concentration during the annealing is investigated analytically thus
allowing us to follow the dependence of laser damage threshold on the fluence
of annealing pulses, their number, and the temperature of the thermostat.
54
Ps24 Photocatalytic evaluation of ferrite nanoparticles synthesized in
palm oil Constantin Virlan, Daniel Gherca, Aurel Pui
Faculty of Chemistry, "Alexandru Ioan Cuza" University, Iasi, Romania
The aim of the present study is to evaluate the photocatalytic activity of
magnetic ferrites, MFe2O4 (M= Mg, Mn, Co, Ni, Cu, Zn) synthesized through
coprecipitation using palm oil as capping agent and surfactant. The
nanoparticles have been synthesised using the coprecipitation method but using
Palm Oil as surfactant and capping agent, a cheap, easy accessible, non-toxic
reagent, this feature representing the innovation factor of the synthesis.
Fig. 1 XRD spectrum of as synthesized MgFe2O4
The as-prepared nanoparticles were characterized by X-ray diffraction
(Figure 1), UV-Vis and FT-IR spectroscopy, SEM imaging as well as regarding
the magnetic properties and surface characterization using BET. The
photocatalytic activity was evaluated on the degradation of various dyes in the
presence of visible light without adding any oxidizing agents. The
photocatalytic activity was evaluated regarding the influence of the divalent
metal in the ferrites. The ferrites as synthesized represent a class of materials
with possible environmental applications due to the ease of separation using a
magnetic field and the fact that they use visible light, much more abundant in
the solar spectrum compared to TiO2 and derivatives that use ultraviolet light.
[1] Erik Casbeer , Virender K. Sharma, Xiang-Zhong Li. Synthesis and photocatalytic
activity of ferrites under visible light: A review, Separation and Purification
Technology, Volume 87, 2012, pages 1–14.
55
Ps25 Structural investigation of surface and biological
properties of some composite resins for dental
reconstruction Diana Diaconu1, Odette Luca1, Stefan Ionita2, Daniel Timpu3, Felicia
Iacomi2,
1Dental Medicine Faculty, Gr.T.Popa University of Medicine, Iasi,
Romania 2Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Iasi,
Romania 3Petru Poni Institute for Macromolecular Chemistry, Iasi, Romania
Nanotechnology induced in dentistry many dental treatment
procedures fast, reliable, safe, and much less painful. Resin
composite materials are popular due to their aesthetic appearance
and wear properties designed to replicate the properties of enamel.
The appearance of a dental restoration is a combination of events
of surface reflection, absorption, and internal scattering. Enamel
naturally displays a high degree of translucency and this is why the
translucency is a desirable characteristic for restorative materials.
In this paper we discuss some surface and biological properties of
a biological structure in comparison with different
photopolymerizable composite resins for dental reconstruction and
correlate them with the structural investigation.
56
Ps26 Structural investigation of Ni- and Co-doped ZnO thin films grown
by spin coating Mihaela Toma, Luciana Punga, Denisa Mihu, Cipriana Padurariu, Vlad
Ifrosie, Stefan Irimiciuc, Marius Dobromir, Valentin Nica, Felicia Iacomi Faculty of Physics, Alexandru Ioan Cuza University of Iasi, Iasi, Romania
Nanocrystalline thin films of low Ni and Co-doped ZnO were deposited
onto glass and quartz substrate by using a spin coating method. Structural,
optical and magnetic properties were investigated by using, X-ray diffraction
(XRD), X-ray photoelectron spectroscopy (XPS) and electron paramagnetic
spectroscopy (EPR). At low doping level, local structure remains identical to
ZnO with subtle increase in the bond length. XPS and the optical absorption
measurements indicate valence +2 both for Ni and Co. Undoped as well as
doped ZnO thin films are weakly ferromagnetic proving that ferromagnetic
ordering in thin films is primarily a manifestation of point defects and
incorporation of transition metal impurities plays a secondary role.
4