Quantum Statistics
239
0
2
4
6
8
T C
T(K)
3
2
1
Resistivity (ohm
– m × 10 )
10
(a)
0
0
2
4
6
8
T(K)
.09
.06
.03
(b)
0
B (tesla)
C
Normal
Superconducting
0
2
4
6
8
T(K)
.06
.04
.02
0
(c)
S u p e r c o n d u c t in g
N o r m a l
C(Joule/mole/K)
Fig. 7.9 (a) Resistivity of a superconductor as a function of T, (b) the critical
magnetic field at which superconductivity disappears, (c) specific heat
in superconducting and normal states.
3. When the current through the superconductor is increased beyond a
critical value I c (T), the superconductor again becomes a normal conductor
[I c (T) = 0 at T = T c ].
4. The specific heat of the material shows an abrupt change at T = T c ,
jumping to a larger value for T < T c [see Fig. 7.9 (c)].