Magnetism (eBook)

Preface 7
Contents 9
1 Introduction 18
1.1 Magnetism: Magical yet Practical 18
1.2 History of Magnetism 20
1.3 Magnetism, Neutrons, Polarized Electrons, and X- rays 29
1.4 Developments in the Second Half of the 20th Century 42
1.5 Some Thoughts about the Future 47
1.6 About the Present Book 49
Part I Fields and Moments 54
2 Electric Fields, Currents, and Magnetic Fields 55
2.1 Signs and Units in Magnetism 55
2.2 The Electric Field 55
2.3 The Electric Current and its Magnetic Field 56
2.4 High Current Densities 61
2.5 Magnetic and Electric Fields inside Materials 63
2.6 The Relation of the Three Magnetic Vectors in Magnetic Materials 65
Hd 65
M B 65
2.7 Symmetry Properties of Electric and Magnetic Fields 73
3 Magnetic Moments and their Interactions with Magnetic Fields 77
3.1 The Classical Definition of the Magnetic Moment 77
3.2 From Classical to Quantum Mechanical Magnetic Moments 80
3.3 Magnetic Dipole Moments in an External Magnetic Field 84
3.4 The Energy of a Magnetic Dipole in a Magnetic Field 85
3.5 The Force on a Magnetic Dipole in an Inhomogeneous Field 88
3.6 The Torque on a Magnetic Moment in a Magnetic Field 100
3.7 Time–Energy Correlation 113
4 Time Dependent Fields 120
4.1 Overview 120
4.2 Basic Concepts of Relativistic Motion 121
4.3 Fields of a Charge in Uniform Motion: Velocity Fields 124
4.4 Acceleration Fields: Creation of EM Radiation 136
5 Polarized Electromagnetic Waves 155
5.1 Maxwell’s Equations and their Symmetries 156
5.2 The Electromagnetic Wave Equation 157
5.3 Intensity, Flux, Energy, and Momentum of EM Waves 159
5.4 The Basis States of Polarized EM Waves 161
5.5 Natural and Elliptical Polarization 169
5.6 Transmission of EM Waves through Chiral and Magnetic Media 173
Part II History and Concepts of Magnetic Interactions 179
6 Exchange, Spin–Orbit, and Zeeman Interactions 180
6.1 Overview 180
6.2 The Spin Dependent Atomic Hamiltonian or Pauli Equation 182
6.3 The Exchange Interaction 188
6.4 The Spin–Orbit Interaction 216
6.5 Hund’s Rules 222
6.6 The Zeeman Interaction 225
7 Electronic and Magnetic Interactions in Solids 234
7.1 Chapter Overview 234
7.2 Localized versus Itinerant Magnetism: The Role of the Centrifugal Potential 236
7.3 The Relative Size of Interactions in Solids 243
7.4 The Band Model of Ferromagnetism 247
7.5 Ligand Field Theory 258
7.6 The Importance of Electron Correlation and Excited States 274
7.7 Magnetism in Transition Metal Oxides 287
7.8 RKKY Exchange 303
7.9 Spin–Orbit Interaction: Origin of the Magnetocrystalline Anisotropy 307
Part III Polarized Electron and X-Ray Techniques 324
8 Polarized Electrons and Magnetism 325
8.1 Introduction 325
8.2 Generation of Spin-Polarized Electron Beams 326
8.3 Spin-Polarized Electrons and Magnetic Materials: Overview of Experiments 330
8.4 Formal Description of Spin-Polarized Electrons 331
8.5 Description of Spin Analyzers and Filters 339
8.6 Interactions of Polarized Electrons with Materials 341
8.7 Link Between Electron Polarization and Photon Polarization 354
9 Interactions of Polarized Photons with Matter 363
9.1 Overview 363
9.2 Terminology of Polarization Dependent Effects 364
9.3 SemiClassical Treatment of X-ray Scattering by Charges and Spins 367
9.4 SemiClassical Treatment of Resonant Interactions 373
9.5 Quantum-Theoretical Concepts 382
9.6 The Orientation-Averaged Intensity: Charge and Magnetic Moment Sum Rules 397
9.7 The Orientation-Dependent Intensity: Charge and Magnetic Moment Anisotropies 413
9.8 Magnetic Dichroism in X-ray Absorption and Scattering 436
10 X-rays and Magnetism: Spectroscopy and Microscopy 442
10.1 Introduction 442
10.2 Overview of Different Types of X-ray Dichroism 443
10.3 Experimental Concepts of X-ray Absorption Spectroscopy 448
10.4 Magnetic Imaging with X-rays 469
Part IV Properties of and Phenomena in the Ferromagnetic Metals 488
11 The Spontaneous Magnetization, Anisotropy, Domains 489
11.1 The Spontaneous Magnetization 490
11.2 The Magnetic Anisotropy 514
11.3 The Magnetic Microstructure: Magnetic Domains and Domain Walls 521
11.4 Magnetization Curves and Hysteresis Loops 525
11.5 Magnetism in Small Particles 527
12 Magnetism of Metals 531
12.1 Overview 531
12.2 Band Theoretical Results for the Transition Metals 533
12.3 The Rare Earth Metals: Band Theory versus Atomic Behavior 540
12.4 Spectroscopic Tests of the Band Model of Ferromagnetism 544
12.5 Resistivity of Transition Metals 558
12.6 Spin Conserving Electron Transitions in Metals 568
12.7 Transitions Between Opposite Spin States in Metals 583
12.8 Remaining Challenges 592
Part V Topics in Contemporary Magnetism 594
13 Surfaces and Interfaces of Ferromagnetic Metals 595
13.1 Overview 595
13.2 Spin-Polarized Electron Emission from Ferromagnetic Metals 596
13.3 Reflection of Electrons from a Ferromagnetic Surface 609
13.4 Static Magnetic Coupling at Interfaces 621
14 Electron and Spin Transport 644
14.1 Currents Across Interfaces Between a Ferromagnet and a Nonmagnet 644
14.2 Spin-Injection into a Ferromagnet 663
14.3 Spin Currents in Metals and Semiconductors 679
14.4 Spin-Based Transistors and Amplifiers 682
15 Ultrafast Magnetization Dynamics 686
15.1 Introduction 686
15.2 Energy and Angular Momentum Exchange between Physical Reservoirs 689
15.3 Spin Relaxation and the Pauli Susceptibility 694
15.4 Probing the Magnetization after Laser Excitation 697
15.5 Dynamics Following Excitation with Magnetic Field Pulses 712
15.6 Switching of the Magnetization 730
15.7 Dynamics of Antiferromagnetic Spins 766
Part VI Appendices 767
A Appendices 768
A.1 The International System of Units (SI) 768
A.2 The Cross Product 770
A.3 s, p, and d Orbitals 771
A.4 Spherical Tensors 772
A.5 Sum Rules for Spherical Tensor Matrix Elements 773
A.6 Polarization Dependent Dipole Operators 774
A.7 Spin–Orbit Basis Functions for p and d Orbitals 775
A.8 Quadrupole Moment and the X-ray Absorption Intensity 776
A.9 Lorentzian Line Shape and Integral 779
A.10 Gaussian Line Shape and Its Fourier Transform 779
A.11 Gaussian Pulses, Half-Cycle Pulses and Transforms 780
References 782
Index 810