Ⅰ Basics

1 Review of basic magnetostatics

1.1 Magnetic field

1.1.1 Magnetic poles

1.1.2 Magnetic flux

1.1.3 Circulating currents

1.1.4 Ampère's circuital law

1.1.5 Biot-Savart law

1.1.6 Field from a straight wire

1.2 Magnetic moment

1.2.1 Magnetic dipole

1.3 Definitions

Homework

2 Magnetization and magnetic materials

2.1 Magnetic induction and magnetization

2.2 Flux density

2.3 Susceptibility and permeability

2.4 Hysteresis loops

2.5 Definitions

2.6 Units and conversions

Homework

3 Atomic origins of magnetism

3.1 Solution of the Schr？dinger equation for a free atom

3.1.1 What do the quantum numbers represent?

3.2 The normal Zeeman effect

3.3 Electron spin

3.4 Extension to many-electron atoms

3.4.1 Pauli exclusion principle

3.5 Spin-orbit coupling

3.5.1 Russell-Saunders coupling

3.5.2 Hund's rules

3.5.3 jj coupling

3.5.4 The anomalous Zeeman effect

Homework

Diamagnetism

4.1 Observing the diamagnetic effect

4.2 Diamagnetic susceptibility

4.3 Diamagnetic substances

4.4 Uses of diamagnetic materials

4.5 Superconductivity

4.5.1 The Meissner effect

4.5.2 Critical field

4.5.3 Classification of superconductors

4.5.4 Superconducting materials

4.5.5 Applications for superconductors

Homework

5 Paramagnetism

5.1 Langevin theory of paramagnetism

5.2 The Curie-Weiss law

5.3 Quenching of orbital angular momentum

5.4 Pauli paramagnetism

5.4.1 Energy bands in solids

5.4.2 Free-electron theory of metals

5.4.3 Susceptibility of Pauli paramagnets

5.5 Paramagnetic oxygen

5.6 Uses of paramagnets

Homework

6 Interactions in ferromagnetic materials

6.1 Weiss molecular field theory

6.1.1 Spontaneous magnetization

6.1.2 Effect of temperature on magnetization

6.2 Origin of the Weiss molecular field

6.2.1 Quantum mechanics of the He atom

6.3 Collective-electron theory of ferromagnetism

6.3.1 The Slater-Pauling curve

6.4 Summary

Homework

7 Ferromagnetic domains

7.1 Observing domains

7.2 Why domains occur

7.2.1 Magnetostatic energy

7.2.2 Magnetocrystalline energy

7.2.3 Magnetostrictive energy

7.3 Domain walls

7.4 Magnetization and hysteresis

Homework

8 Antiferromagnetism

8.1 Neutron diffraction

8.2 Weiss theory of antiferromagnetism

8.2.1 Susceptibility above TN

8.2.2 Weiss theory at TN

8.2.3 Spontaneous magnetization below TN

8.2.4 Susceptibility below TN

8.3 What causes the negative molecular field?

8.4 Uses of antiferromagnets

Homework

9 Ferrimagnetism

9.1 Weiss theory of ferrimagnetism

9.1.1 Weiss theory above TC

9.1.2 Weiss theory below TC

9.2 Ferrites

9.2.1 The cubic ferrites

9.2.2 The hexagonal ferrites

9.3 The garnets

9.4 Half-metallic antiferromagnets

Homework

10 Summary of basics

10.1 Review of types of magnetic ordering

10.2 Review of physics determining types of magnetic ordering

Ⅱ Magnetic phenomena

11 Anisotropy

11.1 Magnetocrystalline anisotropy

11.1.1 Origin of magnetocrystalline anisotropy

11.1.2 Symmetry of magnetocrystalline anisotropy

11.2 Shape anisotropy

11.2.1 Demagnetizing field

11.3 Induced magnetic anisotropy

11.3.1 Magnetic annealing

11.3.2 Roll anisotropy

11.3.3 Explanation for induced magnetic anisotropy

11.3.4 Other ways of inducing magnetic anisotropy

Homework

12 Nanoparticles and thin films

12.1 Magnetic properties of small particles

12.1.1 Experimental evidence for single-domain

particles

12.1.2 Magnetization mechanism

12.1.3 Superparamagnetism

12.2 Thin-film magnetism

12.2.1 Structure

12.2.2 Interfaces

12.2.3 Anisotropy

12.2.4 How thin is thin?

12.2.5 The limit of two-dimensionality

13 Magnetoresistance

13.1 Magnetoresistance in normal metals

13.2 Magnetoresistance in ferromagnetic metals

13.2.1 Anisotropic magnetoresistance

13.2.2 Magnetoresistance from spontaneous magnetization

13.2.3 Giant magnetoresistance

13.3 Colossal magnetoresistance

13.3.1 Superexchange and double exchange

Homework

14 Exchange bias

14.1 Problems with the simple cartoon mechanism

14.1.1 Ongoing research on exchange bias

14.2 Exchange anisotropy in technology

Ⅲ Device applications and novel materials

15 Magnetic data storage

15.1 Introduction

15.2 Magnetic media

15.2.1 Materials used in magnetic media

15.2.2 The other components of magnetic hard disks

15.3 Write heads

15.4 Read heads

15.5 Future of magnetic data storage

16 Magneto-optics and magneto-optic recording

16.1 Magneto-optics basics

16.1.1 Kerr effect

16.1.2 Faraday effect

16.1.3 Physical origin of magneto-optic effects

16.2 Magneto-optic recording

16.2.1 Other types of optical storage, and the future of magneto-optic recording

17 Magnetic semiconductors and insulators

17.1 Exchange interactions in magnetic semiconductors and insulators

17.1.1 Direct exchange and superexchange

17.1.2 Carrier-mediated exchange

17.1.3 Bound magnetic polarons

17.2 Ⅱ-Ⅵ diluted magnetic semiconductors-(Zn,Mn)Se

17.2.1 Enhanced Zeeman splitting

17.2.2 Persistent spin coherence

17.2.3 Spin-polarized transport

17.2.4 Other architectures

17.3 Ⅲ-Ⅴ diluted magnetic semiconductors-(Ga,Mn)As

17.3.1 Rare-earth-group-V compounds-ErAs

17.4 Oxide-based diluted magnetic semiconductors

17.5 Ferromagnetic insulators

17.5.1 Crystal-field and Jahn-Teller effects

17.5.2 YTiO3 and SeCuO3

17.5.3 BiMnO3

17.5.4 Europium oxide

17.5.5 Double perovskites

17.6 Summary

18 Multiferroics

18.1 Comparison of ferromagnetism and other types of ferroic ordering

18.1.1 Ferroelectrics

18.1.2 Ferroelastics

18.1.3 Ferrotoroidics

18.2 Multiferroics that combine magnetism and ferroelectricity

18.2.1 The contra-indication between magnetism and ferroelectricity

18.2.2 Routes to combining magnetism and ferroelectricity

18.2.3 The magnetoelectric effect

18.3 Summary

Epilogue

Solutions to selected exercises

References

Index