15: Superconductivity

Example number 1, Page number 442

In [4]:
#importing modules
import math
from __future__ import division

#Variable declaration
H0=0.0106;          #critical field at 0K(Tesla)
T=3;                #temperature(K)
Tc=4.7;             #temperature(K)

#Calculation
Hc=H0*(1-(T/Tc)**2);     #critical field at 3K(Tesla)

#Result
print "critical field at 3K is",round(Hc,6),"Tesla"
print "answer given in the book is wrong"

critical field at 3K is 0.006281 Tesla
answer given in the book is wrong

Example number 2, Page number 442

In [6]:
#importing modules
import math
from __future__ import division

#Variable declaration
H0=5*10**5/(4*math.pi);          #critical field at 0K(Tesla)
Tc=2.69;                         #temperature(K)
Hc=3*10**5/(4*math.pi);          #critical field(Tesla)

#Calculation
T=Tc*math.sqrt(1-(Hc/H0));       #temperature(K)

#Result
print "temperature of superconductor is",round(T,3),"K"

temperature of superconductor is 1.701 K

Example number 3, Page number 443

In [9]:
#importing modules
import math
from __future__ import division

#Variable declaration
H0=6.5*10**4;          #critical field at 0K(Tesla)
Tc=7.28;               #temperature(K)
T=4.2;                 #temperature(K)
r=1.5*10**-3;          #radius(m)

#Calculation
Hc=H0*(1-(T/Tc)**2);          #critical field(Tesla)
Ic=2*math.pi*r*Hc;            #critical current of the wire(A)

#Result
print "critical field is",round(Hc/10**4,4),"*10**4 A/m"
print "critical current of the wire is",int(Ic),"A"

critical field is 4.3365 *10**4 A/m
critical current of the wire is 408 A

Example number 4, Page number 443

In [11]:
#importing modules
import math
from __future__ import division

#Variable declaration
m1=199.5;             #isotopic mass
m2=205.4;             #change in mass 
Tc1=4.185;            #temperature of mercury(K)

#Calculation
Tc2=Tc1*math.sqrt(m1/m2);     #critical temperature(K)

#Result
print "critical temperature is",round(Tc2,3),"K"

critical temperature is 4.124 K

Example number 5, Page number 444

In [13]:
#importing modules
import math
from __future__ import division

#Variable declaration
T1=3;            #temperature(K)
T2=8;            #temperature(K)
lamda1=39.6;     #penetration depth(nm)
lamda2=173;      #penetration depth(nm)

#Calculation
x=(lamda1/lamda2)**2;
Tc4=(T2**4-(x*T1**4))/(1-x);
Tc=Tc4**(1/4);   #superconducting transition temperature(K)

#Result
print "superconducting transition temperature is",round(Tc,3),"K"

superconducting transition temperature is 8.106 K