The Physics of Ferromagnetism

Springer Series in Materials Science 158......Page 1
The Physics\rof Ferromagnetism......Page 3
Preface......Page 5
Contents......Page 7
Part I Foundation of Magnetism......Page 17
1.1.1 Basic Laws of Magnetic Forces, Magnetic Induction Vector, and Magnetic Moment......Page 19
1.1.2 Vectors of Magnetization, Magnetic polarization and Magnetic field, and Magnetic Polarization Moment......Page 20
1.1.4 Magnetic Vector Potential......Page 21
1.1.6 Magnetic Moment of Current Coil......Page 22
1.1.7 Magnetic Moment of Electron Spin......Page 23
1.1.8 Magnetic Field Strength, Magnetic Induction, Magnetization, Permeability, and Susceptibility......Page 24
1.2.1 Magnetic Charge and Magnetic Coulomb\'s Law......Page 25
1.2.2 Examples of Application of Magnetic Coulomb\'s Law......Page 27
1.2.3 Magnetic Field Produced by Electric Current......Page 29
1.2.5 Magnetic Circuit......Page 30
1.3.1 Zeeman Energy......Page 34
1.3.3 Magnetostatic Energy......Page 35
1.4.1 Principles of Thermodynamics for Magnetic Media......Page 37
1.4.2 Free Energy and Thermal Potential......Page 38
1.4.3 Stabilization Conditions for a System at Constant Temperature......Page 39
1.4.4 First- and Second-Order Transformations......Page 40
1.4.5 Magneto-Caloric Effect......Page 41
1.5.1 Hamiltonian and Momentum in Classical Mechanics......Page 43
1.5.2 Hamiltonian and Momentum in Quantum Mechanics......Page 44
References......Page 49
2.1.1 Electron Spin......Page 51
2.1.2 Hartree--Fock Equations......Page 52
2.1.3 Central Field Approximation......Page 54
2.1.5 Angular Momentum Operators......Page 57
2.2.1 Residual Coulomb Interaction and Term......Page 61
2.2.2 Spin-Orbit Interaction and Multiplet......Page 63
2.3.2 Magnetic Moment and Gyromagnetic Ratio  of an Electron Spin......Page 69
2.3.3 Intrinsic Magnetic Moment, g Factor, and Effective Magnetic Moment of an Atom......Page 70
2.4.1 Magnetic Moment Operator of an Atom in a Magnetic Field......Page 73
2.4.2 Paramagnetism of Atom......Page 74
2.4.3 Diamagnetism of Atom......Page 75
2.5.1 Exchange Hamiltonian......Page 77
2.5.2 Positiveness of Exchange Integral of Form (2.157)......Page 80
2.6.1 Eigenstates and Eigenenergies of the Two Electron  System of H2......Page 81
2.6.2 Exchange Interaction in H2......Page 83
2.7.1 Spin, Magnetic Moment, and Quadrupole of Nucleus......Page 84
2.7.3 Hyperfine Magnetic Interaction......Page 86
2.7.4 Electric-Quadrupole Interaction......Page 88
2.7.6 Total Hyperfine Interaction......Page 89
A4.7 Orthogonal Theorem of the Basis Vectors of Irreducible Unitary Representation and Corresponding Matrix Element Theorems......Page 98
A4.8 Clebsch-Gordan and Racah Coefficients and Coupling  of Irreducible Tensors......Page 99
A5.1 Occupation Number Representation and Creation, Annihilation, and Number Operators......Page 103
A5.2 Second Quantized Representation of One-Particle Hamiltonian......Page 105
A5.3 Second Quantized Representation of Two-Particle Hamiltonian......Page 107
A5.4 Relations Between Creation and Annihilation Operators of Spin-Down and Spin-Up Electrons with Spin Operators......Page 109
References......Page 112
3.1.1 Diamagnetism......Page 113
3.1.2 Paramagnetism......Page 114
3.1.3 Antiferromagnetism......Page 115
3.1.4 Ferromagnetism......Page 116
3.1.6 Magnetic Glass......Page 118
3.1.7 Spin Glass......Page 119
3.2.2 Magnetic Moment of 3d Atom in Alloys......Page 121
3.2.4 Magnetic Moment of 4f Ion in Solids......Page 123
3.3.1 Neutron Diffraction......Page 124
3.3.3 Magnetic Structure of Ho Metal......Page 125
3.3.4 Magnetic Structures of Spinel Ferrites......Page 127
3.3.5 Magnetic Structure of Ba(Sr) Ferrites......Page 128
3.3.6 Magnetic Structures of Rare Earth Iron Garnets......Page 130
3.3.7 Magnetic Structures of Perovskite Ferrites......Page 131
3.3.8 Magnetic Structure of Fe Metal......Page 132
3.4.1 Weiss\'s Molecular Field Theory......Page 133
3.4.2 Néel\'s Molecular Field Theory......Page 136
3.5 Spin Wave......Page 140
3.5.1 Spin Wave......Page 141
3.5.2 Quasiclassical Picture of Spin Wave......Page 144
3.5.3 Bloch T3/2 Law......Page 145
3.6.1 CEF Interactions of 3d and 4f Electrons......Page 147
3.6.2 CEF Hamiltonian......Page 148
3.6.3 CEF Effects for 3d Ion at the B Site of Spinel Ferrite......Page 150
3.6.4 Jahn--Teller Effect......Page 152
3.6.6 Gyromagnetic Effect......Page 153
3.6.7 Precession Motion of Magnetization Vector in a Magnetic Field......Page 155
3.7.1 Eigenstate and Eigenenergy of Free Electron......Page 159
3.7.2 Energy Band of Free Electron Gas......Page 160
3.7.3 Magnetic Properties of Free Electrons......Page 161
3.8.1 Introduction......Page 162
3.8.2 Bloch Wave......Page 163
3.8.3 Band Theory Based on the Mean Field Approximation......Page 164
3.8.4 Stoner Model of Ferromagnetism......Page 166
3.8.5 Density Functional Theory......Page 170
3.8.6 Local Density Approximation and Generalized Gradient Approximation......Page 172
3.8.7 Methods of Energy Band Calculations......Page 173
3.8.8 Examples of Band Structures......Page 175
3.9.1 Hamiltonian of a Nucleus in a Magnetic Field......Page 178
3.9.2 Hyperfine Energy Eigenvalue......Page 180
3.9.3 Hyperfine Magnetic Field......Page 181
3.9.4 Principle of NMR Spectroscopy......Page 182
3.9.5 Principle of Mössbauer Spectroscopy......Page 183
3.9.6 Examples of NMR and Mössbauer Spectroscopy Application......Page 185
References......Page 189
4.1.1 Hamiltonian of One Magnetic Electron Atom System......Page 191
4.1.2 Exchange Hamiltonian in 2......Page 192
4.1.3 Exchange Hamiltonian in 1......Page 193
4.1.4 Total Exchange Hamiltonian......Page 194
4.1.6 Exchange Integral as a Function of Distance Between  a Pair of Atoms......Page 195
4.2.1 Physical Picture of Superexchange Interaction......Page 196
4.2.2 Semi-Quantitative Analysis of Superexchange Interaction......Page 197
4.2.3 Anderson\'s Potential and Kinetic Exchanges......Page 202
4.3 RKKY Exchange Interaction......Page 204
4.3.1 f-s Exchange Hamiltonian ex......Page 205
4.3.2 First-Order Perturbation of ex......Page 206
4.3.3 Oscillatory Decay of Conduction Electron Magnetization......Page 207
4.3.4 Indirect Exchange Interaction Between Rare-Earth Ions......Page 209
4.3.5 Curie Temperature and de Gennes Factor......Page 210
4.4 Double Exchange Interaction......Page 216
4.5.1 Exchange Energy in Cubic Crystals......Page 217
4.5.2 Exchange Energy in Non-Cubic Crystals......Page 219
References......Page 220
5.1.1 Anisotropy of Magnetization Curve of Crystal and Concept  of Magnetocrystalline Anisotropy......Page 221
5.1.2 Phenomenological Expressions of FK......Page 222
5.1.3 Magnetic Anisotropy Field......Page 225
5.2.2 Single-Ion Model......Page 227
5.2.3 Single-Ion Model for 3d Ion......Page 228
5.2.4 Single-Ion Model for 4f Ion......Page 234
5.2.5 Two-Ion Model......Page 239
5.3.2 Demagnetizing Factor and Demagnetizing Energy  of an Ellipsoidal Magnet and Shape Anisotropy......Page 240
5.4.1 Anisotropy of Co Metal Induced by Cooling  in a Magnetic Field......Page 242
5.4.2 Atomic Pair Ordering Anisotropy......Page 243
5.4.3 Shape Anisotropy of Magnetic Film Deposited by Oblique Incidence......Page 245
5.4.4 Magnetization-Induced Anisotropy of Thin Film......Page 246
5.4.5 Magnetic Anisotropy of Alnico Induced by Tempering  in a Magnetic Field......Page 248
5.4.6 Unidirectional Anisotropy of Co-CoO Particles Induced  by Cooling in a Magnetic Field......Page 249
5.4.7 Magnetic Anisotropy of Amorphous Gd-Co Thin Film Easy Axis Normal to the Film Plane......Page 250
5.4.8 Magnetic Field-Induced Anisotropy  of Cu-2%Mn Spin-Glass......Page 251
5.5 Random Anisotropy and Effective Anisotropy......Page 255
5.5.1 Random Anisotropy of Amorphous Magnetic Materials......Page 256
5.5.2 Effective Anisotropy of Amorphous Magnetic Materials......Page 257
References......Page 258
6.1.1 Magnetostriction Phenomena......Page 261
6.1.2 Elastic Mechanics for Cubic Crystal......Page 262
6.1.3 Magneto-Elastic Energy......Page 264
6.1.4 Spontaneous Strain Tensor......Page 265
6.1.5 Phenomenological Expression of Magnetostriction  for Cubic Crystal......Page 266
6.1.6 Phenomenological Expressions of Magnetostriction  for Hexagonal Crystal......Page 267
6.1.7 Origin of Magnetostriction......Page 268
6.2 Stress Energy......Page 271
References......Page 275
7.1 Magnetostatic Energies of Strip and Chessboard Domain Structures......Page 277
7.2.2 General Expressions of the Structure and Energy  of Bloch Wall......Page 280
7.2.3 180° Wall of Easy Axis Crystal......Page 282
7.2.5 180° Wall of Cubic Crystal Under Stress......Page 283
7.2.7 Néel Wall......Page 284
7.3.1 Methods of Domain Observation......Page 285
7.3.2 Analyses of Domain Structures of Easy Axis Crystal Plate......Page 288
7.3.4 Measurement of γw  and A Values......Page 292
7.3.5 Magnetic Bubble......Page 293
7.3.6 Domains in Cubic Crystal Plate......Page 296
7.3.8 Single Domain......Page 298
7.3.9 \"0245Ms  Distribution in Submicron-Scale Dots......Page 300
7.3.10 Superparamagnetism......Page 301
References......Page 302
8.1.1 Brown\'s Equation......Page 303
8.1.2 Nucleation of Magnetization Reversal in Infinite Long Cylindrical Crystal......Page 305
8.2 Finite Element Method......Page 309
8.2.2 Models of Nanocrystalline NdFeB......Page 310
8.2.3 Effects of \"0245H Direction and the Value of N on the Calculation of Hysteresis Curve of Nanocrystalline NdFeB......Page 313
8.2.4 Hysteresis Curve of Nanocrystalline NdFeB......Page 314
References......Page 317
Part II Magnetic Materials......Page 319
9.1.1 Rotation Magnetization......Page 321
9.1.2 Asteroid Curve......Page 324
9.1.3 Magnetic Domain Wall Displacement......Page 326
9.1.4 AC Magnetization and Loss......Page 330
9.2.1 Brief Outline......Page 334
9.2.2 Details of Development Research of Magnetic Metallic  Soft Material......Page 335
References......Page 353
10.1 Requirements on Permanent Magnetic Properties......Page 355
10.2.2 Characteristics of Coercivity Dominated by Nucleation  of Reversed Domain......Page 357
10.2.3 Characteristics of Coercivity Dominated  by Domain Wall Pinning......Page 359
10.2.4 Coercivity of Domain Wall Pinning at Planar Defect......Page 360
10.3 Permanent Magnetic Materials......Page 365
10.3.2 Ba(Sr) Ferrites......Page 366
10.3.3 Alnico......Page 369
10.3.4 FeCrCo......Page 372
10.3.5 PtCo......Page 373
10.3.6 Foundation of Rare Earth Magnets......Page 374
10.3.7 SmCo5......Page 375
10.3.8 SmCoCuFeZr......Page 377
10.3.9 NdFeB......Page 379
10.3.10 Interstitial Sm2Fe17Nx  and NdFe10.5Mo1.5 Nx......Page 383
References......Page 384
Part III Spintronics......Page 387
11.1 History of research......Page 389
11.2.1 Drift Velocity and Fermi Velocity......Page 391
11.2.3 Two-Current Model......Page 393
11.2.4 Resistance Due to Spin Flip......Page 394
11.2.5 Temperature Dependence of ρ......Page 396
11.2.6 How to Obtain uparrow and downarrow......Page 397
11.3 Classification of Magnetoresistance Effects......Page 399
11.4 Anisotropic Magnetoresistance Effect......Page 400
11.5 Origin of Anisotropic Magnetoresistance Effect......Page 402
11.6 Magnetoresistance Curve Based on the Magnetization Rotation Model......Page 408
11.7 Giant Magnetoresistance Effect of Metallic Superlattices and Multilayer Films......Page 409
References......Page 417
12.1.1 Root of Tunnel Effect......Page 419
12.1.2 Root of Magnetoresistance Effect......Page 420
12.2 Principle of TMR......Page 421
12.3 Barrier Height Dependence of TMR Ratio......Page 425
12.4 Comparison Among TMR, AMR, and PHE Effects......Page 426
12.5 Spin Valve-Type Junction with Exchange Bias Layer......Page 428
12.6 Single Crystalline High-Quality Tunnel Junction......Page 430
12.7 Tunnel Junction with MgO Barrier......Page 431
12.8 Tunnel Junction with Half Metal Electrodes......Page 435
12.8.1 Crystal Structure......Page 437
12.8.2 Magnetic Moment, Curie Temperature, and Magnetic Anisotropy......Page 438
12.8.3 Magnetoresistance......Page 440
12.9.1 Giant Magnetoresistance Effect in Granular Structure......Page 444
12.9.3 Organic Molecules-Ferromagnet Hybrid Tunnel Junction......Page 445
References......Page 446
13.1 Introduction......Page 449
13.2 History of Magnetic Memory......Page 450
13.3 Principles......Page 451
13.4.1 Spin Transfer Torque......Page 452
13.4.2 From In-Plane Magnetization to Out of Plane Magnetization......Page 455
13.5.1 High Signal Power Output......Page 457
13.5.3 Low Power Consumption......Page 458
13.5.4 High Reliabilities......Page 459
13.5.5 Making to Large Capacities......Page 460
References......Page 461
14.1 Analysis of the I--V Curve......Page 463
14.2 Inelastic Electron Tunneling Spectroscopy......Page 465
14.3 Conducting Atomic Force Microscope and STM......Page 468
14.4 Measurement of Polarization......Page 470
14.5 Spin Dynamics......Page 474
14.5.1 LLG Equation and Gilbert Damping......Page 475
14.5.2 Experiment......Page 477
14.5.3 Spin Pumping......Page 483
14.5.4 Damping Constant of Various Kinds of Materials......Page 488
References......Page 491
Index......Page 493