Reproduced multi-domain regions during demagnetization in Nd 2 Fe 14 B sintered magnets with different average grain sizes

摘要: Abstract We prepared five Nd2Fe14B sintered magnets with similar saturation polarizations (Js) of 1.38–1.43 T and anisotropy fields (Ha) 6.76–8.52 T, but different grain sizes (DAV) 3.1–8.4 μm in diameter obviously coercivities (μ0Hc) 0.8–1.6 T. The observed difference coercivity could not be explained by the Kronmuller equation, because Ha values chemical compositions microstructures resulting from preparation method except DAV. Hc themselves, however, are inversely proportional to During demagnetization after magnetization a 5 T pulse field, domain wall motion (DWM) was sample μ0Hc = 1.6 T using our step method. DWM also confirmed susceptibility measurements custom-built vibrating magnetometer, generated reproduced multi-domain regions (RMDR) during demagnetization. magnitude as polarization change RMDR samples. Therefore, it should considered that propagation nucleated region through boundary, which corresponds expansion process previous studies, caused by, first, DAV, and, second, boundary state varied final annealing temperature.