Physics of Magnetism

112 CHAPTER 12. PERMANENT MAGNETS In iron metal, one has and a = 0.3nm. The value of may be calculated by means of Eq. (4.4.14), ...

SECTION 12.4. COERCIVITY MECHANISMS 113 reduced with respect to the values in the bulk of the material to make a local magnetiza ...

114 CHAPTER 12. PERMANENT MAGNETS by any applied field. Generally, the value of the coercivity cannot be further increased by ap ...

SECTION 12.5. MAGNETIC ANISOTROPY AND EXCHANGE COUPLING 115 Consequently, the coercive field is equal to the propagation field t ...

116 CHAPTER 12. PERMANENT MAGNETS In lowest order approximation, the anisotropy constants and are related to these crystal-field ...

SECTION 12.5. MAGNETIC ANISOTROPY AND EXCHANGE COUPLING 117 crystal-field parameter is positive. Using Eq. (12.5.2) and the data ...

118 CHAPTER 12. PERMANENT MAGNETS It can be seen in Table 12.5.1 that the advantage of and over is their much higher Curie tempe ...

SECTION 12.6 MANUFACTURING TECHNOLOGIES OF RARE-EARTH-BASED MAGNETS 119 12.6. MANUFACTURING TECHNOLOGIES OF RARE-EARTH-BASED MAG ...

120 CHAPTER 12. PERMANENT MAGNETS by means of ball milling, mortar grinding, or jet milling. In order to avoid oxidation, all mi ...

SECTION 12.6. MANUFACTURING TECHNOLOGIES OF RARE-EARTH-BASED MAGNETS 121 offers the possibility to reach almost perfect particle ...

122 CHAPTER 12. PERMANENT MAGNETS 12.7. HARD FERRITES The ferrites used for permanent-magnet purposes are the hexaferrites, also ...

SECTION 12.7. HARD FERRITES 123 Solid bodies of permanent magnets based on M ferrites can be made either by sintering or by plas ...

124 CHAPTER 12. PERMANENT MAGNETS segments for electric motors, anisotropic rings for loudspeakers, and large anisotropic blocks ...

SECTION 12.8. ALNICO MAGNETS 125 process takes only a very short time when performed at 850°C, being completed in a matter of se ...

126 CHAPTER 12. PERMANENT MAGNETS shape anisotropy in the primary ferromagnetic particles. Since the difference in saturation ma ...

SECTION 12.8. ALNICO MAGNETS 127 of the particles in the field direction occurs because the magnetic free energy of the parti­ c ...

128 CHAPTER 12. PERMANENT MAGNETS A most favorable magnetic property of the Alnico alloys is that these materials have very high ...

SECTION 12.8. ALNICO MAGNETS 129 Kools, F. (1986) in M. B. Bever (Ed.) Encyclopedia of materials science and engineering, Oxford ...

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13 High-Density Recording Materials 13.1. INTRODUCTION Several magnetic materials find an application as thin magnetic films in ...