Nano-sized disorders in hard magnetic grains and their influence on magnetization reversal at artificial Nd/Nd2Fe14B interfaces

Abstract We have investigated the effect of lattice disorders near the surface of hard magnetic Nd 2 Fe 14 B 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 2 Fe 14 B phase at the Nd/Nd 2 Fe 14 B interface of a low coercivity sample, while a high coercivity sample showed a well-defined crystal structure of Nd 2 Fe 14 B near the NdO x /Nd 2 Fe 14 B interface.