1．A Historical Introduction 1
2．Consequences of Fermi Statistics 13
2.1 Quantum Statistics of Fermions 13
2.2 Free Energy of the Fermi Gas 16
3．Paramagnetism 25
4．Energy Bands in the Crystal 31
5．Experimental Basis of Ferromagnetism 37
5.1 Nickel Alloys 42
5.2 Iron Alloys 43
5.3 Palladium Alloys 44
5.4 Iron-Nickel Alloys 44
5.5 Effects of Strong Magnetic Fields 44
5.6 Effects of High Pressure 46
5.7 Effects of Finite Temperature 47
5.8 Susceptibility above Tc 47
5.8.1 Susceptibility of"Classical Spins" 48
5.9 Critical Exponents 50
5.10 Neutron Diffraction 51
5.11 Further Experimental Methods 52
6．Weiss Molecular Field Model 53
6.1 Rhodes-Woblfarth Plot 59
7．Heisenberg Model 63
7.1 Magnon Operators 63
7.2 Heisenberg Hamiltonian in Magnon Variables 66
7.3 Magnon Dispersion Relation 67
7.3.1 Specific Heat of Magnons 69
7.3.2 Ordering Temperature 70
7.4 Approximations for the Heisenberg Model 71
7.4.1 Ising Model 71
7.4.2 XY Model 72
7.4.3 Mean Field Solutions of the Heisenberg Model 73
8．Itinerant Electrons at 0 K 75
8.1 Pauli Susceptibility of the Itinerant Electrons 80
8.2 Susceptibility of the Interacting Itinerant Electrons 80
8.3 Non-linear Effects 83
8.4 Effects of High Fields at 0 K 83
8.4.1 Non-magnetic Limit 84
8.4.2 Strong Ferromagnets 85
8.4.3 Weak Ferromagnets 85
8.4.4 bcc Iron and hcp Cobalt 85
8.4.5 Extremely High Fields 87
8.4.6 Metamagnetism 87
8.5 Susceptibility of Paramagnetic Alloys 89
9．Band Gap Theory of Strong Ferromagnetism 93
9.1 Magnetism of Alloys 97
10．Magnetism and the Crystal Structure-Covalent Magnetism 101
10.1 Crystal Structure of Mn,Fe,Co,and Ni 103
10.2 Covalent Magnetism 105
10.3 Covalent Polarization 111
11．Magnetic Impurities in an Electron Gas 117
11.1 Impurity Potential in the Jellium 117
11.2 Strong Perturbations in the Jellium 119
11.3 Layer and Line Defects 119
11.4 Magnetic Impurities and Oscillations of the Magnetization 120
12．Itinerant Electrons at T＞0:A Historical Survey 123
12.1 Excitations at Low Temperatures 127
12.1.1 Strongly Ferromagnetic Systems 127
12.1.2 Weakly Ferromagnetic Systems 129
12.2 Stoner Theory for a Rectangular Band 130
12.3 Weak Excitations with ζ＜＜1 132
13．Hubbard Model 135
13.1 Beyond Hartree-Fock 137
14．Landau Theory for the Stoner Model 139
14.1 General Considerations 139
14.2 Application to the Stoner Model 141
15．Coupling Between Itinerant and Localized Moments 147
16．Origin of the Molecular Field 151
16.1 Heitler-London Theory for the Exchange Field 151
16.1.1 Magnetism of a Spin Cluster 156
16.1.2 Spinwaves for Localized Electrons 158
17．Exchange and Correlation in Metals 161
17.1 Free Electron Gas 161
17.2 Tightly Bound Electrons 163
18．Spin Fluctuations 169
18.1 Fluctuations of a Thermodynamical Variable 170
18.2 Fluctuations of the Magnetic Moment 171
18.3 Specific Heat of the Spin Fluctuations 177
18.4 Magneto-Volume Coupling 177
18.5 Applications of the Spin Fluctuation Model 179
18.6 Comparing the Spin-Fluctuation and the Stoner-Model 182
19．Single Particle Excitations Versus Spin Waves 185
20．Landau-Ginzburg Model for Spin Fluctuations 191
21．Conclusion and Lookout 199
A．Appendices 203
A．Convexity Property of the Free Energy 203
B．Derivation of the Coefficient a in (3.17) 203
C．Quenching of the Orbital Momentum 206
D．Properties of"Classical"Spins 208
E．Derivation of the Constant c in(8.24) 210
F．Ornstein-Zernicke Extension 211
G．Bogoliubov-Peierls-Feynman Inequality 213
H．The Factor 2 in Equation(7.27) 214
I．Hund's Rules 216
J．Polynomial Coefficients in(18.12) 218
K．Conversion Between Magnetic Units 219
References 221
Index 227