Magnetic Materials and Their Applications

Magnetic Materials and their Applications discusses the principles and concepts behind magnetic materials and explains their applications in the fields of physics and engineering. The book covers topics such as the principal concepts and definitions related to magnetism; types of magnetic materials and their electrical and mechanical properties; and the different factors influencing magnetic behavior. The book also covers topics such as permanent-magnet materials; magnetic materials in heavy-current engineering; and the different uses of magnetic materials. The text is recommended for physicists and electrical engineers who would like to know more about magnetic materials and their applications in the field of electronics.

Contents

Chapter 1

Introduction

Chapter 2

Review of Magnetic Effects

2.1 Preliminary Remarks

2.2 The Most Important Effects

2.2.1 The Joule Effect

2.2.2 The Faraday Effect

2.2.3 The Matteucci Effect

2.2.4 The Wiedemann Effect

2.2.5 The Villau Effect

2.2.6 The Kerr Effect

2.2.7 The Hopkinson Effect

2.2.8 The Cotton-Mouton Effect

2.2.9 The Barnett Effect

2.2.10 The Einstein-de-Haas Effect

2.2.11 The Barkhausen Effect

2.2.12 The magnetothermal Effect

2.2.13 The Hughes Effect

Chapter 3

Magnetic Parameters of Materials

3.1 Types of Magnetic Materials

3.1.1 Paramagnetic Materials

3.1.2 Diamagnetic Materials

3.1.3 Ferromagnetic Materials

3.1.4 Ferrimagnetic Materials

3.1.5 Antiferromagnetic Materials

3.1.6 Metamagnetic Materials

3.2 The Principal Concepts and Definitions

3.2.1 Susceptibility

3.2.2 Magnetic Flux Density

3.2.3 Magnetisation

3.2.4 The Various Permeabilities

3.2.5 Magnetic Losses

3.2.6 Permeability as a Function of Temperature

3.2.7 Losses as a Function of Temperature

3.2.8 Drop in Permeability With Time

3.2.9 Permeability as a Function of Frequency

3.2.10 Losses as a Function of Frequency

3.2.11 Magnetostriction

3.2.12 The Hysteresis Loop

3.2.13 The Demagnetising Factor

3.2.14 Magnetic Anisotropics

Chapter 4

The Magnetising Process and the Basis of the Hysteresis Loop

4.1 The Origin of Magnetism

4.2 Magnetic Domains

4.2.1 Making the Domains Visible

4.2.2 Size and Shape of Domains

4.2.3 The Bloch Wall

4.3 The Magnetising Process

4.3.1 Bloch-wall displacement

4.3.2 Bloch-wall energy

4.3.3 The reversible rotation process

4.3.4 The irreversible rotation process

4.4 Magnetising Processes and the Hysteresis Loop for Polycrystalline Materials

4.4.1 The initial magnetising curve

4.4.2 The limiting loop

4.4.3 The hysteresis family

4.4.4 The ideal magnetising curve

4.5 Magnetising Processes in Single Crystals

4.5.1 The iron single crystal

4.5.2 The nickel single crystal

4.5.3 The cobalt single crystal

4.5.4 Ferrite single crystals

4.6 Micromagnetics

4.7 Magnetisation of Thin Films

4.7.1 The Néel wall

4.7.2 Crosstie walls

4.7.3 Intermediate walls

4.8 The Rayleigh Loop

4.9 The Steinmetz Law

4.10 The Various Segments of the Hysteresis Loop and Their Practical Applications

Chapter 5

The Various Shapes of Hysteresis Loops and Their Physical Causes

5.1 The Normal Hysteresis Loop

5.2 The Rectangular Loop

5.2.1 Rectangular loops in metals

5.2.2 Rectangular loops in ferrites

5.3 Perminvar Loops

5.3.1 Perminvar loops in metals and alloys

5.3.2 Perminvar loops in ferrites

5.3.3 Transformation of Perminvar loops to rectangular shape

5.4 Isoperm Loops

5.4.1 Isoperm loops in metals and alloys

5.4.2 Isoperm loops in ferrites

Chapter 6

Factors Influencing Magnetic Behaviour

6.1 The Influence of Impurities and Low-level Additives

6.1.1 Metallic materials

6.1.2 Oxide materials

6.2 Effect of the Manufacturing Process

6.2.1 Effect of rolling temperature for sheet or strip

6.2.2 Effect of heat treatment on high-permeability materials

6.2.3 Effect of heat treatment on permanent magnets

6.2.4 Effect of sintering on metallic dusts

6.2.5 Effect of sintering conditions on the preparation of ferrites

6.2.6 Shape effects

6.3 Effects due to Mechanical Working

6.3.1 Effect of winding strip cores

6.3.2 Effect of stacking

6.3.3 Effect of resin encapsulation

6.4 Ambient Effects

Chapter 7

Mechanical Properties

7.1 Crystal Structure

7.1.1 Iron

7.7.2 Nickel

7.1.3 Fe-Ni alloys

7.1.4 Cobalt

7.7.5 Cubic ferrites

7.7.6 Hexagonal ferrites

7.2 Density

7.3 Melting Point

7.4 Special Mechanical Properties

Chapter 8

Electrical Properties of Magnetic Materials

8.1 Specific Electrical Resistance

8.1.1 The electrical resistance of metals and alloys

8.1.2 Specific electrical resistance as a function of temperature

8.1.3 The electrical resistance of ferrites

8.2 Dielectric Constant and Loss Angle

8.2.1 Heterogeneous bodies (dust cores)

8.2.2 Ferrites

Chapter 9

Permanent-Magnet Materials

9.1 Role of the Permanent Magnet

9.2 Descriptive Characteristics of Permanent-magnet Materials

9.3 The Optimum Working Point

9.4 Dimensioning a Permanent Magnet

9.5 Fulness Factor

9.6 Stabilising

9.7 Influence of Temperature

9.8 Residual Effect and Ageing

9.9 The Working Line

9.10 The Fundamental Types of Permanent-Magnet Materials

9.10.1 Martensitic steels

9.10.2 Precipitation alloys

9.10.3 Cold-deformed permanent magnets

9.10.4 Superstructure alloys

9.10.5 Materials for dust magnets

9.10.6 Ceramic magnet materials (ferrites)

9.10.7 Materials having exchange anisotropy

9.11 Varieties of Permanent-Magnet Materials Available From Industry

9.12 Applications of Permanent Magnets

Chapter 10

Magnetic Materials in Heavy-Current Engineering

10.1 Requirements for Laminated Materials

10.1.1 Requirements for transformer sheet

10.1.2 Requirements for dynamo sheet and electrosheet

10.1.3 Requirements for materials for level-convertor cores

10.2 Unalloyed Iron

10.3 Fe-Si Alloys

10.3.1 Effect of silicon content

10.3.2 Effect of impurities

10.3.3 Effect of grain size

10.3.4 Temperature dependence of losses

10.3.5 Properties of hot-rolled electrosheet

10.3.6 Cold-rolled Fe-Si sheet

10.4 Fe-Al Alloys

10.5 Fe-Si-Al Alloys

10.6 Fe-Co Alloys

10.7 Ferrite Cores for Power Transformers

Chapter 11

Materials for Transductor Cores

11.1 Principles and Properties of a Transductor

11.2 Transductor Applications

11.3 Requirements for Core Material

11.4 Miscellaneous Materials

11.4.1 Hot-rolled Fe-Si sheet

11.4.2 Grain-oriented Fe-Si sheet

11.4.3 Fe-Ni alloys

11.4.4 Fe-Co alloys

11.4.5 Ferrites

11.5 Effect of Core Construction

Chapter 12

Magnetic Materials for Relays

12.1 Uses and Properties of the Electromagnetic Relay

12.2 Material Requirements for Core and Yoke

12.3 Magnetic Ageing

12.4 Classification of Magnetically Soft Materials for Relays

12.5 Unalloyed Iron

12.6 Fe-Si Alloys

12.7 Fe-Ni Alloys

12.8 Fe-Co Alloys

12.9 Ferrites

Chapter 13

Core Materieals for Inductance Coils and Transformers

13.1 Magnetic Materials in Communications Technology

13.2 Inductively Loaded Conductors

13.3 Specified Requirements for Inductance Coils and Transformer Cores

13.4 Solid Metal and Alloy Core Materials

13.4.1 Core shapes

13.4.2 Types of materials for the cores of communications transformers

13.4.3 Fe-Si alloys

13.4.4 Fe-Al alloys

13.4.5 Fe-Si-Al alloys

13.4.6 Fe-Ni alloys

13.4.7 Fe-Ni-Mo alloys

13.4.8 Fe-Ni-Cr alloys

13.4.9 Fe-Ni-Co alloys

13.4.10 Fe-m-Cu alloys

13.4.11 Fe-Co alloys

13.5 Dust Cores

13.5.1 Core shapes

13.5.2 Comparison of dust cores and laminated cores

13.5.3 Production of dust cores

13.5.4 Properties of dust cores

13.6 Ferrites

13.6.1 Comparison between dust cores and ferrite cores

13.6.2 Core shapes

13.6.3 Adjustable cores

13.6.4 Properties of the more usual ferrites

Chapter 14

Magnetic Materials for the Microwave Region

14.1 Electromagnetic Waves in Waveguides

14.2 The Reciprocity Principle

14.3 Electrical Properties of Ferrites at Super-high F requencies

14.4 Magnetic Properties of Ferrites in a Microwave Field

14.4.1 Permeability

14.4.2 The Faraday effect

14.4.3 Resonance absorption

14.4.4 Field displacement

14.4.5 Effect of specimen shape

14.4.6 Microwave losses

14.4.7 Isolators working on Faraday-absorption and resonance absorption principles

14.4.8 Arrangement of ferrite elements in the waveguide

14.4.9 Bandwidth of an isolator

14.4.10 Effect of temperature

14.5 Materials

14.5.1 Mg-Mn ferrites

14.5.2 Mg-Mn-Al ferrites and Mg-Fe aluminates

14.5.3 Magnesium ferrite-chromite

14.5.4 Manganese ferrites and Mn-Zn ferrites

14.5.5 Nickel ferrite and nickel aluminates

14.5.6 Cobalt ferrite

14.5.7 Hexagonal barium ferrites

14.5.8 Garnets

14.6 Microwave Components using Ferrite

Chapter 15

Magnetic Materials for Information Storage

15.1 Types of Magnetic Store

15.2 Historical

15.3 Tape Recorders

15.3.1 Operating principles

15.3.2 Magnetic tape

15.3.3 Magnetic heads

15.4 Drum Stores

15.4.1 Operation and construction

15.4.2 The magnétisable coating

15.4.3 Magnetic heads

15.4.4 Detailed examples of drum stores

15.5 Magnetic Disc Stores

15.6 Toroidal Core Stores

15.6.1 Principle of operation

15.6.2 The cyclic magnetising or flux-reversal process

15.6.3 Requirements for core materials

15.6.4 Characteristic curves of a memory core

15.6.5 Core materials

15.7 Ferrite Storage Plates

15.8 Thin-film Stores

15.8.1 Manufacture of thin films

15.8.2 Materials used for magnetic films

15.8.3 The magnetic spot

15.8.4 The storage element and its functioning

15.8.5 The switching process in film elements

15.8.6 Advantages and disadvantages of plane film storage elements

15.9 Cylindrical Thin-film Storage Elements

15.10 The Waffle-iron Memory Store

15.11 Transfluxors

15.11.1 Working principles of a transfluxor

15.11.2 Applications of transfluxors

15.11.3 Transfluxor materials

15.12 The Twistor

15.13 The Magnetostrictive Delay Line

15.14 The Orthoferrite Memory

Chapter 16

Materials for Magnetomechanical Resonators

16.1 Applications

16.2 Requirements Specified for the Material

16.3 The Magnetomechanical Coupling Factor

16.4 Forms of Mechanical Oscillator

16.5 Example of a Magnetostrictive Filter

16.6 Materials

16.6.1 Metals and alloys

16.6.2 Ferrites

Chapter 17

Materials for Magnetic Shielding

17.1 Stray-field Effects

17.2 Operation of a Shield

17.3 The Shielding Factor

17.4 Magnetic-shield Materials

Chapter 18

Materials for Temperature Compensation

18.1 Problem and Principles

18.2 Materials

18.2.1 Metallic compensation materials

18.2.2 Ferrites

Chapter 19

Tables

19.1 Tables of Materials

19.1.1 Permanent-magnet materials

19.1.2 Sheet and strip

19.1.3 Ferrites for inductance coils and communications transformers

19.1.4 Ferrites for microwave applications

19.1.5 Core materials for storage and switching devices

19.2 Trade Names and Producers of Magnetic Materials