Abstract
The domain wall motion in the multi-domain particles in Sm2Fe17N3(SFN)powder reacted with Zn metal samples was studied.In the samples, 2 wt.% of SFN particles were homogeneously, isotropically distributed in Zn metal powder, and pressed under 20 MPa, followed by heat-treatment at various temperatures. The saturable multi-domain particles (SMDP) in the sample powders were magnetized into the single-domain state after the pulse magnetization in 5 T. The magnetization reversal in SMDP after magnetization became difficult in the heat-treated samples. The reversal behavior, which can be detected by susceptibility measurements, should be the origin of the enhancement of coercivity. For example, the coercivity (μoH) is about 0.4 T larger in the 623 K treated sample than that of the untreated sample. The direct observation of the domain structures before and after the magnetization in untreated SMDP was also curried out using magnetic force microscopy (MFM).
