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A study concentrates on the effects of the substitution of Si for Fe on the magnetic properties of Tb(sub2)Fe(sub17) compounds. An exchange interaction of the Fe-Fe and Tb-Fe and magnetocrystalline anisotropy constants to the sixth order were examined. There was confirmation of the narrow domain wall-pinning effect and calculations of the Si dependence of the domain wall thickness and energy were made.

The composition dependence of the magnetic moment and the Curie temperature in a series of quaternary CuCoMnAl alloys are analyzed to phenomenologically study the ferromagnetic exchange interaction between Co and Mn in Heusler alloys. The short-range effect observed for the ferromagnetic Co-Mn exchange interaction which is only effective at the nearest-neighhor distance could be enhanced by a Mn-rich composition.

[Co.sub.0.8][Mn.sub.x][Fe.sub.2.2-x][O.sub.4] (x = 0.2, 0.4, 0.6, and 0.8) powders are prepared by a sol-gel process and annealed at different temperatures and magnetic and structural properties are measured. The decrease in coercivity ([H.sub.c]) is attributed to the content decrease in [Co.sup.2+] on B sites and increasing grain sizes at higher annealing temperature have an intensive influence on [H.sub.c].

Scanning electron acoustic microscopy (SEAM) and magnetic force microscopy (MFM) are used for examining the magnetic domain structure of [Fe.sub.81][Ga.sub.19] alloys under compressive and grinding stresses. The subdomains of as-cast sample has shown a clear dendritic structure and the results have helped in understanding the magnetostrictive behavior of Fe-Ga alloys under stress.

Contrast origin of magnetic domain structure imaged by scanning electron acoustic microscopy (SEAM) is analyzed by exploring the interaction between an incident electron beam and a sample. The contrast origin of magnetic domain structure in electron acoustic image (EAI) is discussed by considering the affect of spontaneous magnetization.

Structure and magnetic properties of the Ho-substituted [Nd(sub 1-x)Ho(sub x)](Sub 3)Fe(sub 23-y)Co(sub 6)V(sub y) compounds is discussed. It can be seen that the B(sub a) increases first from x=0 to 0.5, going through a maximum at x=0.5, then decreases with further increasing Ho content.

Effects of Mo content on the structure stability of R3(Fe,Co,Mo)(sub 29) compounds are presented in comparison with the substitution behavior of Cr in the Gd3[Fe (sub 1-x)Co(sub x)](sub 29-y)Cr(sub y) compounds. These results show that it is promising to search a material with high magnetic properties in the R(sub 3)Fe(sub 29-x-y)Co(sub x)Mo(sub y) compounds, due to the low nonmagnetic Mo content in these compounds.