MAGNETIZATION REVERSAL PROCESS OF ZN-BONDED ANISOTROPIC SM-FE-N PERMANENT-MAGNETS

Zn-bonded anisotropic Sm-Fe-N permanent magnets were prepared by annealing fine-powdered Sm2Fe17 particles first in hydrogen and then in nitrogen atmosphere, and followed by mixing with Zn powder, compressing in a magnetic field, and finally annealing. The coercive fields Hc of Zn-bonded anisotropic Sm-Fe-N permanent magnets were measured in the temperature interval from 5 to 700 K. The temperature dependence of Hc was analyzed within the framework of the micromagnetic models. Nucleation of reversed domains, preferentially at misaligned grains on the grain surface where the demagnetizing field is the largest, is determined to be the leading mechanism in controlling the magnetization reversal process of Zn-bonded anisotropic Sm-Fe-N permanent magnets. For comparison, results on isotropic mechanically alloyed magnets are also presented. © 1995 The American Physical Society.