Nanomagnetism and Spintronics

Cover Page......Page 1
Copyright......Page 2
Preface......Page 3
Introduction......Page 5
Discovery of GMR......Page 7
Development of GMR Studies......Page 10
Further Progress in MR Experiments......Page 13
The Scope of this Book......Page 15
References......Page 16
GMR, TMR and BMR......Page 18
Introduction......Page 19
Electronic states and magnetism in transition metals and alloys......Page 21
α-parameter......Page 22
Spin-dependent resistivity due to ferromagnetic impurities in novel metals......Page 24
Two-band model......Page 26
Microscopic Theory of Electrical Conductivity: Linear Response Theory......Page 27
Current parallel to planes......Page 28
Current perpendicular to layer planes......Page 30
Recursive Green\'s function method......Page 31
Conductance quantization and Landauer formula......Page 32
Magnetic multilayers......Page 33
GMR and exchange coupling......Page 34
CPP-GMR......Page 37
Granular GMR......Page 39
Phenomenological theory of GMR......Page 40
Electronic states and spin-dependent resistivity in multilayers......Page 41
Estimate of GMR using spin-dependent potentials......Page 42
Microscopic theory of GMR......Page 44
Effects of spin-flip scattering......Page 46
Ferromagnetic tunnel junctions......Page 48
MR ratio and spin polarization......Page 49
Spin polarization......Page 50
Free-electron model......Page 51
Ingredients for TMR......Page 52
Effects of Fermi surface......Page 53
Effect of interfacial states......Page 54
Effect of electron scattering......Page 55
Voltage dependence......Page 57
Fe/MgO/Fe......Page 58
Oscillation of TMR......Page 59
Tunnel junctions with half-metals......Page 62
Ferromagnetic tunnel junctions with manganites......Page 63
Tunnel junctions with Heusler alloys......Page 65
Tunnel junctions with diluted magnetic semiconductors......Page 67
Tunnel conductance in granular systems......Page 68
Granular TMR......Page 70
Coulomb-blockade TMR......Page 72
Ballistic Magnetoresistance......Page 73
Paramagnetic metals......Page 74
Ferromagnetic metals......Page 75
Interpretation of BMR......Page 77
Normal MR......Page 78
Anisotropic magnetoresistance......Page 79
Colossal magnetoresistance......Page 81
Spin-orbit interaction......Page 82
Anomalous Hall effect......Page 83
Spin Hall effect......Page 85
Rashba 2DEG and spin accumulation......Page 87
Acknowledgements......Page 88
References......Page 89
Spin-Injection Phenomena and Applications......Page 96
Spin injection......Page 97
Spin-transfer torque......Page 108
Field-like torque......Page 113
Amplification of the precession......Page 114
Cylindrical pillar with uniaxial anisotropy......Page 116
Linearized LLG equation and instability current......Page 118
Spin-injection magnetization switching......Page 120
Switching time and thermal effects......Page 123
Elliptical pillar with an in-plane magnetization......Page 124
High-speed measurements......Page 127
Spin-transfer oscillation......Page 132
Spin-torque diode effect......Page 138
From Spin-Transfer Torque Ram to Magnetic Logic......Page 142
The magnetic random access memory......Page 143
Towards magnetic logic......Page 148
Acknowledgements......Page 150
Out-of-plane magnetization case......Page 151
References......Page 152
Dynamics of Magnetic Domain Walls in Nanomagnetic Systems......Page 157
Introduction......Page 158
Detection of domain-wall propagation by using GMR effect......Page 159
Ratchet effect in DW motions......Page 162
DW velocity measurements......Page 165
Concept of current-driven DW motion......Page 169
MFM direct observations......Page 171
Towards applications of current-driven DW motion......Page 173
MFM studies on magnetic vortices in dot systems......Page 177
Current-driven resonant excitation of magnetic vortex......Page 180
Switching a vortex core by electric current......Page 183
References......Page 187
Theoretical Aspects of Current-Driven Magnetization Dynamics......Page 190
Introduction......Page 191
Field-driven domain-wall motion......Page 192
Phenomenological equation of motion......Page 193
Equations of motion from microscopic spin dynamics......Page 194
Lagrangian formulation......Page 197
Interaction of domain wall and electron flow: An intuitive picture......Page 199
Mathematical derivation......Page 201
Supplementary remarks......Page 202
Dynamics......Page 204
Dynamics driven by spin transfer......Page 205
Dynamics driven by both spin transfer and force......Page 207
Microscopic Calculation of Spin Torques......Page 209
General......Page 210
Intuitive picture......Page 212
Microscopic model......Page 214
Results......Page 215
Adiabatic spin frame and gauge field......Page 217
Gilbert damping......Page 218
Force......Page 219
Relation to transport coefficients......Page 220
Current-driven motion of magnetic vortices......Page 222
Equation of motion......Page 223
Current-driven dynamics......Page 224
Lagrangian formalism......Page 225
Current-induced spin-wave instability......Page 226
References......Page 227
Micromagnetics of Domain-Wall Dynamics in Soft Nanostrips......Page 231
Micromagnetics......Page 232
Numerical micromagnetics......Page 234
The symmetric transverse wall (STW)......Page 235
Energies and phase diagram......Page 237
Panorama......Page 239
Linear regime (steady state)......Page 240
Motion above the Walker field......Page 243
Propagation field......Page 245
Comparison to experiments......Page 247
CIP spin transfer in micromagnetics......Page 248
The OEligrsted field......Page 251
Sample temperature......Page 252
Transverse wall......Page 254
Vortex wall......Page 256
Comparison to experiments......Page 258
Linear regime......Page 259
Lagrangian formulation of micromagnetics under CIP STT......Page 260
Beyond the Walker regime......Page 262
Linear regime......Page 263
Comparison to experiments......Page 264
Transverse wall......Page 265
Vortex wall......Page 267
Linear regime......Page 269
Above the Walker breakdown regime......Page 270
Imperfect nanostrip case......Page 271
AC effects......Page 272
Conclusions and Outlook......Page 273
References......Page 274
III-V-Based Ferromagnetic Semiconductors......Page 277
Introduction......Page 278
Molecular Beam Epitaxy......Page 279
Structural characterization of (Ga,Mn)As......Page 281
Magnetic properties of (Ga,Mn)As......Page 283
Magnetic domain......Page 284
Magnetic anisotropy......Page 285
Hall effect and hole concentration......Page 287
Low-temperature annealing......Page 288
Magnetotransport properties......Page 290
Critical scattering......Page 291
Domain wall resistance......Page 292
Magneto-optical properties......Page 293
The sp-d Exchange Interaction......Page 294
The p-d Zener Model of Ferromagnetism......Page 296
Electrical spin injection into non-magnetic semiconductors......Page 297
Tunnel magnetoresistance (TMR) and current-induced magnetization switching (CIMS)......Page 299
Current-induced domain wall motion......Page 301
Control of magnetism and magnetization reversal by external means......Page 303
Prospects......Page 306
References......Page 307
B......Page 316
D......Page 318
F......Page 319
G......Page 320
H......Page 321
K......Page 322
L......Page 324
M......Page 325
N......Page 326
O......Page 327
R......Page 328
S......Page 329
T......Page 331
V......Page 332
Y......Page 333
Z......Page 334
C......Page 335
D......Page 336
F......Page 337
G......Page 338
M......Page 339
R......Page 341
S......Page 342
T......Page 343
Z......Page 344