Nano-sized disorders in hard magnetic grains and their influence on magnetization reversal at artificial Nd/Nd_2Fe_(14)B interfaces

摘要

We have investigated the effect of lattice disorders near the surface of hard magnetic Nd2Fei4B grains on coercivity using artificial interfaces created by sputter depositing Nd on polished surface of Nd-Fe-B sintered magnets. The interfacial structure was manipulated by annealing the coated samples at 550 °C in vacuum with and without Ta cap. Nano-beam electron diffraction revealed a few nm thick disordered layer within the Nd_2Fe_(14)B phase at the Nd/Nd2Fe_(14)B interface of a low coercivity sample, while a high coercivity sample showed a well-defined crystal structure of Nd_2Fe_(14)B near the NdO_x/Nd_2Fe_(14)B interface.