Coercivity Enhancement of Nd-Fe-B Thin Film Magnets through Dy Surface Diffusion Process

C.Y. You1,2), J. Zhu1), N. Tian2) and Z.X. Lu2) 1) State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China 2) School of Materials Science and Engineering, Xi an University of Technology, Xi an 710048, China

摘 要：The Dy capping layer was deposited at different temperatures on the Nd-Fe-B thin films to investigate the mechanism of the coercivity enhancement through the Dy surface diffusion. The highest coercivity of 2005 kA/m （25.2 kOe） was obtained at the Dy deposition temperature of 460℃, which was significantly higher than the value of 1297 kA/m （16.3 kOe） without Dy capping layer. By performing the transmission electron microscopy （TEM） analysis, it was found that some of the grain boundaries were enriched with Nd element, which could be partly ascribed to the promotion by the Dy surface diffusion. In comparison to the evolution of the spin reorientation temperature of Nd2Fe14B phase after the deposition of the Dy capping layer, it is concluded that structural modification plays a significant role in the coercivity enhancement due to the Dy surface diffusion.

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