colossal magnetoresistance in metals: a miracle?
DESCRIPTION
Colossal Magnetoresistance in Metals: a Miracle?. Jiunn-Yuan Lin. Giant Magnetoresistance in Metals: a Miracle?. Jiunn-Yuan Lin. Collabrations. W. J. Chang, S. W. Huang, T.-Y. Chung, S. Y. Hsu, and J.-Y. Juang Department of Electrophysics, NCTU H. T. Jeng - PowerPoint PPT PresentationTRANSCRIPT
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?