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Low field ac susceptibility and magnetization curves of milled Sm2Fe17N3 powders are measured for isotropic and aligned samples with average particle sizes ranging from 3.0 to 52 microns. Most of the particles are in a multidomain state before application of a magnetic field. The transverse ac susceptibility due to magnetization rotation against the anisotropy field is independent of particle size. The parallel ac susceptibility and the susceptibility of isotropic powders are dominated by almost free domain wall movement in multidomain particles.

The magnetic characteristics of sintered Sm2Fe17Ny magnets prepared by explosion sintering were investigated. The results showed that explosion sintering was more efficient than the conventional epoxy-resin bonding process. The explosion sintered magnet featured better rectangularity of the magnetization curve. The coercivity of the explosion sintered magnet was thought to originate from the nucleation in the grain surface layer.

The results from an ac-susceptibility search for spin reorientation transitions within Dy(sub2)Fe(sub17-x)Gax where an anomalous temperature dependence of Xac was found, are presented. Decreasing temperatures lead to a spin reorientation from an easy axis to an easy cone occurs. The Ga substitution is found to have a strong effect on the low temperature anomaly, although it has little effect on the high temperature anomaly.

Electronic structure and hyperfine fields have been calculated for antiferromagnetic YFe(sub6)Sn(sub6) using a linear muffin-tin orbital technique. Fe atoms were found to have strong ferromagnetic character, and the hyperfine field was close to the experimental value of 22 T measured at low temperature. Core s electrons contribute 24 T to the hyperfine field.