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{
"metadata": {
"name": ""
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 12: Superconductivity"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.1, Page 373"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import pi\n",
"\n",
"#Variable declaration\n",
"Tc=7.26;#critical tempreture in kelvin\n",
"H0=8*1e5/(4*pi);#magnetic field at 0K\n",
"T=5;#tempreture in kelvin\n",
"\n",
"#Calculation\n",
"Hc=H0*(1-(T/Tc)**2);#megnrtic field at 5K\n",
"\n",
"#Result\n",
"print 'magnrtic field at 5K tempreture =%.2f*10^4 A/m'%(Hc/1e4)\n",
"#Incorrect answer in the textbook\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"magnrtic field at 5K tempreture =3.35*10^4 A/m\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.2, Page 373"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import log\n",
"\n",
"#Variable declaration\n",
"Tc=0.3;#given tempareture in kelvin\n",
"thetad=300;\n",
"\n",
"#Calculations&Results\n",
"#part a\n",
"N0g=-1./(log(Tc/thetad));\n",
"print 'the value of N0g is %.2f'%N0g\n",
"#part b\n",
"kB=1.38*1e-23;#boltzmann constant\n",
"Eg=3.5*kB*Tc;#energy\n",
"print 'energy is= %.2f*10^-23 J'%(Eg/1e-23)\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"the value of N0g is 0.14\n",
"energy is= 1.45*10^-23 J\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.3, Page 374"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable declaration\n",
"H0=0.0306;#given constant characteristic of lead material\n",
"Tc=3.7;#given tempareture in kelvin\n",
"T=2;#given tempareture in kelvin\n",
"\n",
"#Calculations\n",
"x=(T/Tc)*(T/Tc);\n",
"Hc=H0*(1-x);#value of magnetic field at 2K temp\n",
"\n",
"#Result\n",
"print 'value of magnetic field at 2K temp = %.4f T'%Hc\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"value of magnetic field at 2K temp = 0.0217 T\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.4, Page 374"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import sqrt,pi\n",
"\n",
"#Variable declaration\n",
"HcT=2*1e5/(4*pi);#magnetic field intensity at T K\n",
"Hc0=3*1e5/(4*pi);#magnetic field intensity at T=0K\n",
"Tc=3.69;#given temperature in K\n",
"\n",
"#Calculation\n",
"T=sqrt(1-(HcT/Hc0))*Tc;#tempreture in K\n",
"\n",
"#Result\n",
"print 'temperature of superconducture is= %.2f K'%T\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"temperature of superconducture is= 2.13 K\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.5, Page 374"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import pi\n",
"\n",
"#Variable declaration\n",
"H0=6.5*1e4;#given constant characteristic of lead material\n",
"Tc=7.18;#given temprature in kelvin\n",
"T=4.2;#given temprature in kelvin\n",
"\n",
"#Calculations&Results\n",
"#part a\n",
"x=(T/Tc)*(T/Tc);\n",
"Hc=H0*(1-x);#value of magnetic field at 4.2K temp\n",
"print 'value of magnetic field at 4.2K temp= %.2f*10^4 A/M'%(Hc/1e4)\n",
"#part b\n",
"r=1e-3;#given radius\n",
"Ic=2*pi*r*Hc;#critical current\n",
"print 'critical current is = %.1f A'%Ic #Incorrect answer in the textbook\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"value of magnetic field at 4.2K temp= 4.28*10^4 A/M\n",
"critical current is = 268.7 A\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12.6, Page 375"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from math import sqrt\n",
"\n",
"#Variable declaration\n",
"lemdaT=750;#given penetration depth at T=3.5K\n",
"Tc=4.22;#given critical tempreture\n",
"T=3.5;##given temperature\n",
"\n",
"#Calculations&Results\n",
"#part a\n",
"x=(T/Tc)**4;#temporary variable\n",
"lemda0=lemdaT/sqrt(1-x);#penetration depth at T=0K\n",
"print 'penetration depth at T=0K is %.fA'%lemda0\n",
"#part b\n",
"N=6.02*1e26;#given\n",
"alpha=13.55*1e3;#given\n",
"M=200.6;#given\n",
"n0=N*alpha/M;\n",
"print 'molecular density = %.3f*10^28 /m^3'%(n0/1e28)\n",
"ns=n0*(1-(T/Tc)**4);#superconducting electron density\n",
"print 'superconducting electron density = %.3f*10^28 /m^3'%(ns/1e28)#Answer differs due to rounding-off values\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"penetration depth at T=0K is 1033A\n",
"molecular density = 4.066*10^28 /m^3\n",
"superconducting electron density = 2.142*10^28 /m^3\n"
]
}
],
"prompt_number": 6
}
],
"metadata": {}
}
]
}
|
