Interfacial state and magnetic properties of Nd-Fe-B/Nd thin films

Nd-Fe-B/Nd(-O) interfaces were prepared by thin film technique for the investigation of relationship between interfacial state and coercivity. A Nd-Fe-B layer was deposited by UHV magnetron sputtering and the film was oxidized under low vacuum conditions. On the oxidized Nd-Fe-B layer, a Nd layer was deposited and the film was annealed at 250 - 650 ° C . The coercivity of Nd-Fe-B layer decreased after the oxidation. However, it recovered after the deposition of Nd layer and the annealing at 350 ° C . High-resolution transmission electron microscopy (HRTEM) observations revealed that an fcc NdO phase forms after the oxidation and an amorphous phase exists along the interface between Nd 2 Fe 14 B and Nd 2 O 3 phases after annealing at 350 ° C . Therefore, the recovery of coercivity is related to the amorphous phase, which is considered to be formed by the transformation from NdO to Nd 2 O 3 and α -Nd , and the release of strain at the interface.