colossal magnetoresistance in metals: a miracle?

Colossal Magnetoresistance in Metals: a Miracle?

Jiunn-Yuan Lin

Giant Magnetoresistance in Metals: a Miracle?

Jiunn-Yuan Lin

CollabrationsW. J. Chang, S. W. Huang, T.-Y. Chung, S. Y. Hsu, and J.-Y. Juang• Department of Electrophysics, NCTUH. T. Jeng• Institute of Physics, Academia SinicaC. P. Sun, and H. D. Yang • Department of Physics, NSYUSH. Berger• Institute of Physics of Complex Matter, EPFL, Lausanne, Switzerland

J. M. Chen, and K. Liang• NSRRC

Subbayah Pullavar photo by P. Y. Plunkett (June 6, 1936)

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 3000.00

0.05

0.10

0.15

0.20

0.25

0.30

R

T(K)

old-0804Pb-warming(08192005)PPMS

0 20 40 60 80 1000.00

0.05

0.10

R

T(K)

old-0804Pb-warming(08192005)PPMS

constant.` a is and )1(

)( ,

)(4 :

0 2

5

5

L

dzeezxwhere

TTformulaBloch

x

z

zn

n

0.0 0.2 0.4 0.6 0.8 1.0 1.20.0

0.2

0.4

0.6

0.8

1.0

1.2 Bloch formula RPb 83 K

R

/R0

T/

Experiment result

H. Berger (Department of Physics, EPF Lausanne, CH-1015 Lausanne, Switzerland).

0 50 100 150 200 250 3000

100

200

300

400 Cd2Re

2O

7

(

c

m)

T (K)

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.350.00

0.05

0.10

0.15

0.20

0.25

Bloch formula RCd2Re2O7 132 K

R

/R0

T/

Atomic coordinates (x104) –160K x y z________________________________ Re 2471(2) 0 8729(2)Cd 0 2471(4) 6259(3)O11 3059(15) 1941(15) 7500O12 0 0 8026(16)O13 1889(16) 1889(16) 10000O14 5000 0 9317(19)O21 0 0 5000O22 0 5000 7500________________________________

Atomic coordinates (x 104)--295K

x y z________________________

_ Re 2500 7500 50

00Cd 5000 5000 50

00O(1) 3152(9) 6250 62

50O(2) 6250 6250 62

50________________________

__Atomic coordinate (x104) – 90K x y z_______________________________Re 2500 -33(3) 8750Cd 5041(6) 2500 11250O11 1880(20) 1880(20) 10000O12 5000 0 9396(14)O13 1970(20) -1970(20) 10000O2 5000 5000 10000_______________________________

Space group: Fd-3m for high I4-m2 for middle I4122 for low

High temperature Intermediate temperature & low temperature

0 10 20 30 40 50 60 70 80 900.0000

0.0005

0.0010

0.0015

0.0020

0.0025

0.0030

0.0035

0.0040

0 Tesla 1 Tesla 3 Tesla 6 Tesla 9 Tesla

R

esis

tanc

e (O

hm)

Temperature (K)

0 10 20 300.0000

0.0005

0 Tesla 1 Tesla 3 Tesla 6 Tesla 9 Tesla

R

esis

tanc

e (O

hm)

Temperature (K)

0 1 2 3 4 5 6 7 8 90.00000

0.00003

0.00006

0.00009

0.00012

0.00015

0.00018

R

(Ohm

)

H (Tesla)

at 0.40 K

0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

0.00000

0.00001

0.00002

0.00003

0.00004

0.00005

0.00006

0.00007

0.00008

0 Tesla 0.05 Tesla 0.10 Tesla 0.15 Tesla 0.20 Tesla

R

esis

tanc

e (O

hm)

Temperature (K)

0 20000 40000 60000 800000.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

2 K 10 K 20 K 50 K 90 K 116 K 150 K 205 K 300 K

(R

(H)-R

(0))/R

(0)

H(Oe)

Cd2Re

2O

7 R/R~H

=1.33=1.33

Baibichi et al., PRL (1988)

“simple” metals in the magnetic fields

JHJE

00

mq

The two band model for magnetoresistance

22221

221

222121

0 )()()(

HH

0 20000 40000 60000 800000.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

22221

221

222121

0 )()()(

HH

2002 D. J. Singh et al (PRB vol. 65 155109) VASP GGA-PAW-SO-666

2002 H. Harima (Jon. Of Phys. and Chem.Solid)

X-files• Mulder: Scully, would you be afraid if there is no God?• Scully: What I am afraid is: God is talking to us, but nobody is listening.

• There are indeed miracles around us (and in the labs).

• The question is : did you notice?