Particle interaction during magnetization reversal process of anisotropic Sm₂Fe₁₇N_x powders

The particle interaction during magnetization reversal process is important for the applications and magnetic properties improvement of Sm₂Fe₁₇N_x powders. In this paper, an anisotropic Sm₂Fe₁₇N_x powder free of α-Fe was prepared by ball milling. The magnetically soft Sm₂Fe₁₇ powders with different particle sizes were added into the α-Fe-free Sm₂Fe₁₇N_x powder as easy nucleation sites, and the effects of these magnetically soft phases on the magnetization reversal process were investigated quantitatively. It is found that the squareness of Sm₂Fe₁₇N_x powder decreases obviously with the increasing number of Sm₂Fe₁₇ particle and the demagnetization curves can be divided into two stages. The magnetization reversal process suggests that the addition of magnetically soft powder should only reduce the coercivity of a specific part of Sm₂Fe₁₇N_x particles and the reversed domain walls cannot move easily across neighboring Sm₂Fe₁₇N_x particles. Based on the observed magnetization reversal process, the mechanical properties of magnetically soft phase should be considered in the preparation of anisotropic Sm₂Fe₁₇N_x powders.