Magnetic Materials and Their Applications

ContentsChapter 1IntroductionChapter 2Review 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 EffectChapter 3Magnetic 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 AnisotropicsChapter 4The 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 ApplicationsChapter 5The 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 ferritesChapter 6Factors 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 EffectsChapter 7Mechanical 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 PropertiesChapter 8Electrical 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 FerritesChapter 9Permanent-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 MagnetsChapter 10Magnetic 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 TransformersChapter 11Materials 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 ConstructionChapter 12Magnetic 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 FerritesChapter 13Core 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 ferritesChapter 14Magnetic 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 FerriteChapter 15Magnetic 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 MemoryChapter 16Materials 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 FerritesChapter 17Materials for Magnetic Shielding 17.1 Stray-field Effects 17.2 Operation of a Shield 17.3 The Shielding Factor 17.4 Magnetic-shield MaterialsChapter 18Materials for Temperature Compensation 18.1 Problem and Principles 18.2 Materials 18.2.1 Metallic compensation materials 18.2.2 FerritesChapter 19Tables 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