MAGNETIC REVERSAL IN SINGLE-PHASE NANOCRYSTALLINE SM-FE-N ALLOYS AND A 2-PHASE REMANENCE ENHANCED (SM2FE17N3-FE) ALLOY(ALPHA)

The nucleation fields of isotropic nanocrystalline single-phase Sm-Fe- N magnets prepared by mechanical alloying have been determined experim entally. Single-phase Sm-Fe-N magnets possess a distinct angular depen dence of the nucleation field, giving rise to a nucleation-controlled magnetic reversal process. The influence of the substitution of Co and Ti for Fe is discussed. Additionally, two-phase (Sm2Fe17Nx + alpha-fe ) alloys have been investigated by measuring the perpendicular and the parallel components of the magnetization and their remanence. Remanen ce enhancement has been observed; that is, the magnetic reversal in th ese two-phase alloys is strongly affected by intergrain exchange inter action. This may give rise to cascades of magnetization reversal due t o collective processes. A phenomenological explanation of the magnetic reversal in these systems is suggested.