Magnetic intrinsic

Electrons and most other fiindamental particles have two distinct spin wavefunctions that are degenerate in the absence of an external magnetic field. Associated with these are two abstract states which are eigenfiinctions of the intrinsic spin angular momentum operator S... 

The intrinsic properties may be modified by substitution (31). Ba can be fuUy replaced by Sr or Pb and partly by Ca (<40 mol %). CaM, stabilized with 0.03 mol % La202, is also possible. The intrinsic properties of these M-ferrites vary somewhat and other factors such as sintering behavior and price of raw materials often dictate the commercial viabiUty. Large-scale production is concentrated on BaM and SrM. High quaUty magnets are generally based on SrM, and somewhat lower priced magnets are based on BaM. 

Substitution for Fe has a drastic effect on intrinsic magnetic properties. Partial substitution by or decreases J) without affecting seriously, resulting in larger and values. Substitution by Ti and Co causes a considerable decrease in K , the uniaxial anisotropy (if j > 0) may even change into planar anisotropy (if < 0). Intermediate magnetic stmctures are also possible. For example, preferred directions on a conical surface around the i -axis are observed for substitution (72). For a few substitutions the value is increased whereas the J) value is hardly affected, eg, substitution of Fe byRu (73) or by Fe compensated by at Ba-sites (65). 

Magnet Applications. For magnets of the type FeNdB, a small amount of gallium is effective in improving the intrinsic coercive force (53). It slows the pinning type recoil loop. The thermal stabiUty is increased. The irreversible loss is less than 1.5% under 373 K (1000 h). 

Intrinsic and Extrinsic Properties. The materials Fe, Co, and Ni and their alloys and oxides are mostly used for recording appHcations materials. Their magnetic properties are described by intrinsic and extrinsic parameters. The intrinsic properties (saturation magneti2ation, Af,... 

H, for which J = 0, is the intrinsic coercivity whereas the usual coercivity, for which S = 0, is denoted by H or H. For permanent magnets, the value (BH), the maximum energy product, is an important measure of quaHty. The value (BH), iadicated ia the secoad quadrant of Figure 1, represents the poiat of maximum efficieacy where a givea amouat of magnetic flux is produced by the smallest amouat of material. 

Table 12. Intrinsic Properties of Ternary R-Based Magnetic Materials ...

With respect to magnetic properties, the intrinsic magnetic susceptibiHty of pure chrysotile is very weak. However, the presence of associated minerals such as magnetite, as weU as substitution ions (Fe, Mn), increases the magnetic susceptibiHty to values around 6 x 10 m /kg. With amphiboles, the magnetic susceptibiHty is much higher, mainly because of the high iron content typically, amosite and crocidoHte exhibit susceptibiHty values of 100 and 75 X 10 m /kg, respectively (23). 

The Stern-Gerlach experiment demonstrated that electrons have an intrinsic angular momentum in addition to their orbital angular momentum, and the unfortunate term electron spin was coined to describe this pure quantum-mechanical phenomenon. Many nuclei also possess an internal angular momentum, referred to as nuclear spin. As in classical mechanics, there is a relationship between the angular momentum and the magnetic moment. For electrons, we write... 

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