Coercivity mechanism and magnetization reversal of anisotropic La-Nd-Dy-Fe-B micron-sized films

Abstract

The coercivity mechanism and magnetization reversal process of anisotropic La-Nd-Dy-Fe-B micron-sized films have been investigated. By varying the thickness of the single-layer film from 500 nm to 6 μm, the highest coercivity of 1.88 T in the film with 3 μm thickness is achieved at 300 K, due to the large dipole interaction and domain pinning effect. When the thickness is further increased to 6um, the coercivity decreases sharply to 1.11T due to the microstructure and phase formation in the film. In the 6 μm multilayer film, the addition of a Ta spacer layer further enhances perpendicular magnetic anisotropy, the dipole interaction, and adjusts the phase distribution, collectively boosting the coercivity of the micron-sized film (1.63 T). As thickness of the film increases, the dominant mechanism of coercivity shifts from a pinning mechanism to a nucleation mechanism. This study contributes to the understanding of the coercivity mechanism and magnetization reversal process in La-Nd-Dy-Fe-B permanent magnet micron-sized films.