superconductivity david kelley ecpe 131 12-09-2002
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SuperconductivitySuperconductivity
David KelleyDavid Kelley
ECPE 131ECPE 131
12-09-200212-09-2002
What is Superconductivity?What is Superconductivity?
State/Phase of matter with unique electrical, State/Phase of matter with unique electrical, magnetic, and thermal properties.magnetic, and thermal properties.
1.1. The Discovery of SuperconductivityThe Discovery of Superconductivity
2.2. Properties Exhibited by Superconductive MaterialsProperties Exhibited by Superconductive Materials
3.3. The BCS Theory of SuperconductivityThe BCS Theory of Superconductivity
4.4. High Temperature Superconductivity (HTSC)High Temperature Superconductivity (HTSC)
5.5. The Current State of Research in HTSCThe Current State of Research in HTSC
6.6. Development of Superconductive TechnologyDevelopment of Superconductive Technology
7.7. Obstacles of SuperconductivityObstacles of Superconductivity
8.8. Concluding RemarksConcluding Remarks
1. The Discovery of 1. The Discovery of Superconductivity Superconductivity
Onnes – Liquefaction of HeliumOnnes – Liquefaction of Helium Tests of electrical resistance of HgTests of electrical resistance of Hg
NomenclatureNomenclature
TTC C – Critical Temperature– Critical Temperature
HHCC – Critical Magnetic Field – Critical Magnetic Field
2. The Properties Exhibited by 2. The Properties Exhibited by Superconductive MaterialsSuperconductive Materials
Zero electrical resistance / Perfect conductionZero electrical resistance / Perfect conduction
Perfect Diamagnetism (The Perfect Diamagnetism (The Meissner EffectMeissner Effect))
Type II SuperconductorsType II Superconductors
Incomplete Meissner effectIncomplete Meissner effect
3. How Superconductivity Works3. How Superconductivity Works(The BCS Theory)(The BCS Theory)
Fritz London – ‘Giant Fritz London – ‘Giant Atom’Atom’
Cooper pairsCooper pairs
Scattering – Scattering – phononsphonons
No scattering – No scattering – Virtual PhononsVirtual Phonons
More on Cooper PairsMore on Cooper Pairs Equal but opposite momentum/opposite spinEqual but opposite momentum/opposite spin
Momentum pairMomentum pair
Equalibrium – 0 net momentumEqualibrium – 0 net momentum
Cooper pairs are dynamicCooper pairs are dynamic
Discrete energyDiscrete energy
Energy to alter the momentum of an Energy to alter the momentum of an electronelectron
Cooper pairs always have the same Cooper pairs always have the same momentummomentum
Energy to alter the momentum of a horde of Energy to alter the momentum of a horde of cooper pairscooper pairs
Bandgap and TBandgap and TCC
Discrete energy required to excite an Discrete energy required to excite an electron across bandgap (break cooper pair)electron across bandgap (break cooper pair)
Not all materials with large bandgaps Not all materials with large bandgaps become superconductive – cooper pairsbecome superconductive – cooper pairs
4. High Temperature 4. High Temperature Superconductivity (HTSC)Superconductivity (HTSC)
Limits of the BCS theoryLimits of the BCS theory
Bednorz and Muler: 30KBednorz and Muler: 30K
90K… 125K (3 groups)90K… 125K (3 groups)
If the BCS theory failed how does it work?If the BCS theory failed how does it work?
‘‘Giant Atom’ – New Electron Giant Atom’ – New Electron MediatorMediator
Common themes amongst Common themes amongst HTSCHTSC
Pervoskite – copper planesPervoskite – copper planes
5. The current state of research5. The current state of research
Mott insulators and dopingMott insulators and doping
Copper planes cause ‘resonating valence Copper planes cause ‘resonating valence bonds’ – antiparallel electron configurationbonds’ – antiparallel electron configuration
Non copper oxide HTSCNon copper oxide HTSC
Field effect doping superconductivity Field effect doping superconductivity
6. Superconductive Technology6. Superconductive Technology
Long distance power transmissionLong distance power transmission Energy storageEnergy storage InterconnectsInterconnects MRIMRI
MaglevMaglev
Particle AcceleratorsParticle Accelerators
7. Obstacles7. Obstacles
Critical temperatureCritical temperature Mechanical propertiesMechanical properties Technology InertiaTechnology Inertia No one knows how it really works?No one knows how it really works?
8. Concluding remarks8. Concluding remarks
Useful for magnetic and electric propertiesUseful for magnetic and electric properties
Must balance TMust balance TCC and H and HGG with other qualities with other qualities
No complete theory for HTSC, perhaps we No complete theory for HTSC, perhaps we missed something with low temp SCmissed something with low temp SC
Field effect dopingField effect doping
AcknowledgementsAcknowledgements Buckel, Werner. Superconductivity: Fundamentals and Applications. Buckel, Werner. Superconductivity: Fundamentals and Applications.
Weinheim, Germany: VCH Verlagsgesellschaft mbH, 1991.Weinheim, Germany: VCH Verlagsgesellschaft mbH, 1991. Iovine, John. “Superconductors.” Poptronics. July 2000. November, 2002.Iovine, John. “Superconductors.” Poptronics. July 2000. November, 2002.
<http://web7.infotrac.galegroup.com/itw/infomark/965/565/26215720w7/<http://web7.infotrac.galegroup.com/itw/infomark/965/565/26215720w7/purl=rc1_EAIM_0_A63667028&dyn=11!xrn_3_0_A63667028?purl=rc1_EAIM_0_A63667028&dyn=11!xrn_3_0_A63667028?sw_aep=uop_demo >sw_aep=uop_demo >
Kresin, Vladimir Z. and Stuart A. Wolf. Fundamentals of Superconductivity. Kresin, Vladimir Z. and Stuart A. Wolf. Fundamentals of Superconductivity. New York: Plenum Press, 1990.New York: Plenum Press, 1990.
Orlando, Terry, and Kevin A. Delin. Foundations of Applied Superconductivity. Orlando, Terry, and Kevin A. Delin. Foundations of Applied Superconductivity. Reading, Massachusetts: Addison-Wesley Publishing Company Inc., 1991.Reading, Massachusetts: Addison-Wesley Publishing Company Inc., 1991.
Pines, David, and Ulam Scholar. Understanding High Temperature Pines, David, and Ulam Scholar. Understanding High Temperature Superconductivity: Progress and Prospects. Center for Nonlinear Studies at Superconductivity: Progress and Prospects. Center for Nonlinear Studies at Los Alamost National Laboratory and Physics Department, University of Illinois: Los Alamost National Laboratory and Physics Department, University of Illinois: 10-28-02. <http://cnls.lanl.gov/Highlights/1997-06/html/June_97.html>10-28-02. <http://cnls.lanl.gov/Highlights/1997-06/html/June_97.html>
Superconductivity for Electric Systems. U.S. Department of Energy: 10-28-02. Superconductivity for Electric Systems. U.S. Department of Energy: 10-28-02. <http://www.eren.doe.gov/superconductivity/><http://www.eren.doe.gov/superconductivity/>
Vidali, Gianfranco. Superconductivity: The Next Revolution? Cambridge: Vidali, Gianfranco. Superconductivity: The Next Revolution? Cambridge: Cambridge University Press, 1993.Cambridge University Press, 1993.