Introduction to Magnetism and Magnetic Materials Second edition David Jiles Ames Laboratory, US Department of Energy Department of Materials Science and Engineering and Department of Electrical and Computer Engineering, Iowa State Universe, Arnes, Iowa, USA CHAPMAN & HALL/CRC A CRC Press Company Boca Raton London New York Washington, D.C. Contents Preface to the first edition vii Preface to the second edition ix Foreword xi Acknowledgements xvii Glossary of symbols xxiii ST units, symbols and dimensions xxix Values of selected physical constants xxxi Part 1 Electromagnetism — magnetic phenomena on the macroscopic scale 1 1 Magnetic fields 3 1.1 The magnetic field 3 1.2 Magnetic induction 9 1.3 Magnetic field calculations 18 References 32 Further reading 33 Exercises 33 2 Magnetization and magnetic moment 35 2.1 Magnetic moment 35 2.2 Magnetic poles and Amp8rian bound currents 40 2.3 Magnetization 44 2.4 Magnetic circuits and demagnetizing field 48 2.5 Penetration of alternating magnetic fields into materials 57 References 61 Further reading 61 Exercises 61 3 Magnetic measurements 65 3.1 Induction methods 65 3.2 Force methods 71 3.3 Methods depending on changes in material properties 76 3.4 SQUIDS 83 xiv Contents References 86 Further reading 86 Exercises 86 4 Magnetic materials 89 4.1 Classification of magnetic materials 89 4.2 Magnetic properties of ferromagnets 91 4.3 Different types of ferromagnetic materials for applications 96 4.4 Paramagnetism and diamagnetism 103 References 108 Further reading 109 Exercises 109 5 Magnetic properties 111 5.1 Hysteresis and related properties 111 5.2 The Barkhausen effect and related phenomena 119 5.3 Magnetostriction 121 5.4 Magnetoresistance 128 References 129 Further reading 130 Exercises 130 Part 2 Magnetism in materials — magnetic phenomena an the microscopic scale 133 6 Magnetic domains 135 6.1 Development of domain theory 135 6.2 Energy considerations and domain patterns 146 References 153 Further reading 154 Exercises 154 7 Domain walls 157 7.1 Properties of domain boundaries 157 7.2 Domain-wall motion 168 References 175 Further reading 176 Exercises 176 8 Domain processes 179 8.1 Reversible and irreversible domain processes 179 8.2 Determination of magnetization curves from pinning models 189 8.3 Theory of ferromagnetic hysteresis 198 8.4 Dynamics of domain magnetization processes 205 Contents xv References 212 Further reading 214 Exercises 215 9 Magnetic order and critical phenomena 217 9.1 Theories of paramagnetism and diamagnetism 217 9.2 Theories of ordered magnetism 228 9.3 Magnetic structure 239 References 258 Further reading 260 Exercises 260 10 Electronic magnetic moments 263 10.1 Classical model of magnetic moments of electrons 263 10.2 Quantum mechanical model of magnetic moments of electrons 266 10.3 Magnetic properties of free atoms 280 References 288 Further reading 289 Exercises 289 11 Quantum theory of magnetism 291 11.1 Electron—electron interactions 291 11.2 The localized electron theory 301 11.3 The itinerant electron theory 309 References 319 Further reading 320 Exercises 320 Part 3 Magnetics — technological applications 323 12 Soft magnetic materials 325 12.1 Properties and applications 325 12.2 Materials for a.c. applications 329 12.3 Materials for d.c. applications 350 12.4 Materials for magnetic shielding 356 References 359 Further reading 360 13 Hard magnetic materials 363 13.1 Properties and applications 363 13.2 Permanent magnet materials 376 References 391 Further reading 393 xvi Contents 14 Magnetic recording 395 14.1 Magnetic recording media 395 14.2 Recording heads and the recording process 409 14.3 Modeling the magnetic recording process 419 References 420 Further reading 421 15 Magnetic evaluation of materials 423 15.1 Methods for evaluation of intrinsic properties 423 15.2 Methods for detection of flaws and other inhomogeneities 433 15.3 Magnetic imaging methods 447 15.4 Conclusions 453 References 455 Further reading 457 Solutions 459 Appendix 1: The magnetic field as a relativistic correction to the electric field 511 Appendix 2: Derivation of Maxwell's equation from the relativistic Lorentz transformation 515 Author index 521 Subject index 529.