Modern Hard Magnetic Materials

Ferromagnetism: magnetization curves

“…Whether or not a field is applied, there must, however, be some relation between the orientation of the segregate and that of the crystal in which it is formed. Measurements of magnetostriction of alcomax by Hoselitz and McCaig (1949) are consistent with the view that, after cooling in a magnetic field, the easiest directions of magnetization (i.e. the directions of the domain magnetization vectors in the absence of a field) are along or near the cubeedge directions which are nearest to the anisotropy axis of the specimen.…”

“…Stoner 1934Stoner , 1948 have sections on ferromagnetic materials, Among the more comprehensive review articles dealing with ferromagnetic materials generally are those of Kussmann (1935Kussmann ( , 1939 and Webb (1938). Soft materials are surveyed by Yensen (1939Yensen ( , 1948, and hard by Hoselitz (1946). A recent most valuable review of progress on magnetic materials by Brailsford et al (1948) contains sections on electrical sheet steels , permanentmagnet materials (Oliver and Hadfield 1948) and magnetic powder cores (Polgreen 1948).…”

A mechanism of magnetic hysteresis in heterogeneous alloys

“…Magnets made of sintered powders of permanent magnet alloy material are finding increasing practical application (cf. Hoselitz 1946), but these are of less theoretical interest than magnets made up of small particles of, say, pure iron. If the particles are small enough to be of single-domain character, and are sufficiently distorted from a spherical to a prolate spheroidal form, such magnets, with a sufficiently large 'filling factor', offer a theoretical possibility of (£//)m ax> values greatly exceeding those at present obtained.…”

“…There is, finally, one remarkable effect which should be mentioned in relation to the present treatment, namely the effect of cooling in a magnetic field on alloys of the alcomax or ticonal types. Demagnetization curves and some particulars of composition and treatment are given in a recent review article by Hoselitz (1946). The salient effect of cooling in a field is that in the direction in which the field has been applied the remanence, coercivity, and 'fullness' are all increased, and in a perpendicular direction decreased.…”

New characteristic parameter of energy loss in permalloy

“…Consequently, it is hard to describe the spectrum with intrinsic quantities such as saturation magnetization M s , anisotropic field H K , and damping factor α easily. Refer to the importance of maximum magnetic energy product (BH) max [32] in hard magnetic materials, characteristic parameters of energy storage and loss are urgent to be introduced. It is known that the initial susceptibility χ i determines the susceptibility of metallic SMMs within working frequency range, and the resonance frequency ω r determines the highest working frequency of metallic SMMs as shown in figure 1.…”