Coercivity mechanism of La-Nd-Fe-B films with Y spacer layer

The effect of the Y spacer layer on the phase composition, coercivity, and magnetization reversal processes of La-Nd-Fe-B films has been investigated. The addition of a 10 nm Y spacer layer increases the coercivity of the film to 1.36 T at 300 K and remains 0.938 T at 380 K. As the thickness of the Y spacer layer increases, Y participates in the formation of the main phase in the film, and further regulates the formation of La-B phases. The results of the first-order reversal curve (FORC) and micromagnetic fitting show that the coercivity of all the films is dominated by nucleation mechanism. The c-axis preferred orientation, good magnetic microstructure parameters and the largest dipole interaction enhance the coercivity. Therefore, the introduction of the Y spacer layer can be an effective way to improve the coercivity of La-Nd-Fe-B film over a wide temperature range of 150 K-380 K.