Magnetic oxides / Gerald F. Dionne.

Format:

Book

Author/Creator:

Dionne, G. F. (Gerald F.)

Language:

English

Subjects (All):

Oxides--Magnetic properties.

Oxides.

Physical Description:

xiii, 466 pages : illustrations ; 25 cm

Place of Publication:

New York : Springer, [2009]

Summary:

Magnetic Oxides offers a cohesive up-to-date introduction to magnetism in oxides. Emphasizing the physics and chemistry of local molecular interactions essential to the magnetic design of small structures and thin films, this volume provides a detailed view of the building blocks for new magnetic oxide materials already advancing research and development of nano-scale technologies.

Clearly written in a well-organized structure, readers will find a detailed description of the properties of magnetic oxides through the prism of local interactions as an alternative to collective electron concepts that are more applicable to metals and semiconductors. Researchers will find Magnetic Oxides a valuable reference.

Contents:

1 Introductory Magnetism 1

1.1 Fundamental Concepts and Definitions 1

1.1.1 Basic Electrostatics 2

1.1.2 Basic Magnetostatics 3

1.1.3 Demagnetization in Uniformly Magnetized Bodies 4

1.1.4 Domains in Partially Magnetized Bodies 6

1.2 Induced Magnetism 8

1.2.1 Diamagnetism and Paramagnetism 8

1.2.2 Temperature Dependence of Susceptibility 11

1.3 Spontaneous Magnetism 15

1.3.1 Classical Ferromagnetism and Antiferromagnetism 15

1.3.2 Solutions of the Brillouin-Weiss Equation 16

1.3.3 Quantum Origins of the Molecular Field 19

1.3.4 The Ising Approximation 24

1.4 Gyromagnetism 25

1.4.1 Larmor Precession and Resonance 26

1.4.2 Phenomenological Relaxation Theory 27

1.4.3 Complex Susceptibility Theory 29

1.4.4 Resonance Line Shapes 33

Appendix 1A Spin-Lattice Contribution to Linewidth 34

References 35

2 Magnetic Ions in Oxides 37

2.1 The Transition Metals 37

2.1.1 The Periodic Table 38

2.1.2 Iron Group 3d n Ions 40

2.1.3 Rare Earth 4f n " Ions 42

2.1.4 4d" and 5d n Ions 42

2.2 Oxygen Coordinations 43

2.2.1 Crystal Systems and Point Groups 44

2.2.2 Cubic Symmetry 45

2.2.3 Lower Symmetries 47

2.3 Crystal Electric Fields 48

2.3.1 Angular Momentum States 49

2.3.2 Crystal Field Hamiltonian 50

2.3.3 Hierarchy of Perturbations 54

2.3.4 Weak-Field Solutions 55

2.3.5 Group Theory and Lower Symmetry 64

2.3.6 Strong Field Solutions and Term Diagrams 68

2.3.7 Rare-Earth Ion Solutions 71

2.4 Orbital Energy Stabilization 73

2.4.1 One-Electron Model 73

2.4.2 High- and Low-Spin States 75

2.4.3 Orbit-Lattice Stabilization (Jahn-Teller Effects) 79

2.4.4 Spin-Orbit-Lattice Stabilization 82

2.5 Covalent Stabilization 88

2.5.1 Molecular-Orbital Theory 89

2.5.2 Determinant Method 91

2.5.3 αand φ; Bonds and the Molecular Orbital Diagram 95

2.5.4 Valence Bond Method 99

Appendix 2A Homonuclear Molecule Ion 102

Appendix 2B Valence-Bond Diatomic Molecule 103

References 105

3 Magnetic Exchange in Oxides 107

3.1 Interionic Magnetic Exchange 108

3.1.1 Molecular-Orbital Exchange Approximation 109

3.1.2 Valence-Bond Solutions 113

3.1.3 Spin Alignment in Oxides 119

3.1.4 Ferromagnetism by Spin Transfer 121

3.1.5 Goodenough-Kanamori Rules 125

3.2 Antiferromagnetism 129

3.2.1 Superexchange and Molecular Fields 129

3.2.2 Molecular Field Theory of Antiferromagnetism 131

3.2.3 Antiferromagnetic Spin Configurations 135

3.3 Antiferromagnetic Oxides 139

3.3.1 One-Metal Oxides 139

3.3.2 A B0₃ and A₂ B0₄ Perovskites 140

3.3.3 The Mixed-Valence Manganite Anomaly 143

Appendix 3A Analysis of M 2+ 0 2- Exchange Interactions 146

Appendix 3B Curie Temperature Model for (La,Ca) Mn0₃ 147

References 149

4 Ferrimagnetism 151

4.1 Ferrimagnetic Order 151

4.1.1 Generic Ferrimagnetic Systems 152

4.1.2 Molecular Field Theory of Ferrimagnetism 153

4.1.3 Magnetic Frustration and Spin Canting 157

4.2 Theory of Superexchange Dilution 161

4.2.1 Superexchange Energy Stabilization 161

4.2.2 Molecular Field Coefficients 164

4.2.3 Solution for Yttrium Iron Garnet 165

4.3 Ferrimagnetic Oxides 168

4.3.1 Spinel Ferrites A [B₂]0₄ 169

4.3.2 Garnet Ferrites (c₃)[a₂(d₃O₁₂ 175

4.3.3 Rare-Earth Garnet Ferrites 180

4.3.4 Rare-Earth Canting Effect 184

4.3.5 Hexagonal Ferrites 190

4.3.6 Orthoferrites 193

Appendix 4A Molecular Field Analysis of LiZnTi Ferrite 193

Appendix 4B High-Magnetization Limits 195

Appendix 4C Brillouin Functions in Exchange Energy Format 196

References 197

5 Anisotropy and Magnetoelastic Properties 203

5.1 Quantum Paramagnetism of Single Ions 202

5.1.1 Theory of Anisotropic g Factors 202

5.1.2 Conventional Perturbation Solutions 205

5.1.3 The Spin Hamiltonian for 3d n Ions 209

5.1.4 The Crystal-Field Hamiltonian for 4/ n Ions 210

5.2 Anisotropy of Single Ions 212

5.2.1 3d¹ and3d⁶ D-StateTriplet 213

5.2.2 3d⁴ and 3d⁹ D-State Doublet (J-T Effect) 217

5.2.3 3d² and 3d⁷ F-State Triplet 219

5.2.4 3d² and 3d⁸ F-State Singlet 220

5.2.5 3d⁵ S-State Singlet 222

5.2.6 Af n Ion Anisotropy 226

5.3 Magnetocrystalline Anisotropy and Magnetostriction 228

5.3.1 Phenomenological Anisotropy Theory 229

5.3.2 Phenomenological Magnetostriction Theory 231

5.3.3 Dipolar Pair Model of Magnetic Anisotropy 234

5.3.4 Single-Ion Model of Ferrimagnetic Anisotropy 236

5.3.5 Cooperative Single-Ion Effects: Anisotropy 241

5.3.6 Cooperative Single-Ion Effects: Magnetostriction 246

5.4 Magnetization Process and Hysteresis 250

5.4.1 Initial Permeability and Coercivity 251

5.4.2 Anisotropy Field and Remanence Ratio 254

5.4.3 Approach to Saturation 256

5.4.4 Demagnetization and Permanent Magnets 258

Appendix 5A Four-Level Degenerate Perturbation Solution for d¹ 261

Appendix 5B T 2g Solution for d l in an Exchange Field 263

Appendix 5C Orbital States of d⁵ in a Cubic Field 265

Appendix 5D Angular Dependence of Cubic Anisotropy Fields 267

References 269

6 Electromagnetic Properties 273

6.1 Magnetic Relaxation 274

6.1.1 Nonresonant Longitudinal Relaxation 274

6.1.2 Quantum Mechanisms of Spin-Lattice Relaxation 278

6.1.3 Perturbation Theories of Spin-Phonon Interaction 286

6.2 Gyromagnetic Resonance and Relaxation 287

6.2.1 Paramagnetic Resonance 288

6.2.2 Ferromagnetic Resonance 292

6.2.3 Uniform Precession Damping 295

6.2.4 Inhomogeneous Resonance Line Broadening 297

6.2.5 Fast-Relaxing Ion Effects 300

6.2.6 The Exchange Isolation Effect 306

6.3 Exchange-Coupled Modes (Spin Waves) 307

6.3.1 Uniform Precession Decoherence (Degenerate Spin Waves) 307

6.3.2 Instability Threshold (Classical Approximation) 311

6.3.3 Instability Threshold (Nonlinear Spin Waves) 315

6.3.4 Magnetostatic Modes 317

6.4 Permeability and Propagation 318

6.4.1 Low-Frequency Longitudinal Permeability 318

6.4.2 High-Frequency Transverse Limits 322

6.4.3 Snoek's Law Considerations" 324

6.4.4 Circular Polarization and Nonreciprocal Properties 327

6.4.5 Linear Polarization and Faraday Rotation 332

Appendix 6A Transverse Permeability Tensor 333

Appendix 6B Classical Instability Threshold 336

Appendix 6C Domain Wall Susceptibility Equation 338

References 340

7 Magneto-Optical Properties 343

7.1 Infrared Exchange Resonance 344

7.1.1 Classical Precession Model 344

7.1.2 Quantum Spin Transition Model 346

7.1.3 Experimental Exchange Spectra 351

7.2 Combined Permeability and Permittivity 352

7.2.1 The [ε]ʺ[μ] Tensor Solutions 352

7.2.2 Propagation Parameters and Faraday Rotation 353

7.3 Magneto-Optical Spectra 355

7.3.1 Electric-Dipole Transitions 355

7.3.2 Yttrium Iron Garnet Spectra (Paramagnetic) 360

7.3.3 Iron Garnets with Bismuth Ions (Diamagnetic) 366

7.3.4 Fe 3+ -Bi 3+ Hybrid Excited States 371

7.3.5 Intersublattice Transitions and the ΔS = 0 Rule 376

Appendix 7A Magnetic Circular Birefringence and Dichroism 381

References 382

8 Spin Transport Properties 385

8.1 Polarons and Charge Transfer 386

8.1.1 Transfer Among Equivalent Energy Sites (Small Polarons) 388

8.1.2 Transfer to Higher Energy Sites (Large Polarons) 389

8.1.3 Transfer by Covalent Tunneling 392

8.1.4 The Holstein Polaron Theory 394

8.2 Metallic Oxides with Polarized Spins 396

8.2.1 Simple Oxides 397

8.2.2 Complex Oxides 397

8.2.3 Classical Resistivity-Temperature Model 400

8.3 Magnetoresistance in Oxides (CMR) 401

8.3.1 Manganese-Ion Exchange Interactions 402

8.3.2 Magnetoresistivity-Temperature Model 405

8.3.3 Dilute Magnetic Oxides 410

8.4 Superconductivity in Oxides 413

8.4.1 Classical Foundations 413

8.4.2 Zero-Spin Polarons and Magnetic Frustration 419

8.4.3 Large-Polaron Superconductivity 423

8.4.4 Normal Resistivity and Critical Temperature 426

8.4.5 Layered Cuprate Superconductors 430

8.5 Supercurrents and Magnetic Fields 439

8.5.1 Supercurrent Formation 439

8.5.2 Condensation Energy 442

8.5.3 London Penetration Depth 443

8.5.4 Critical Magnetic Field 445

8.5.5 Critical Current Density 447

8.5.6 Coherence Length 450

8.5.7 Type-II Superconductors 452

Appendix 8A Magnetic Levitation 455

References 456.

Notes:

Includes bibliographical references and index.

ISBN:

9781441900531

1441900535

OCLC:

320494954