Magnetization reversal behavior and first-order reversal curve diagrams in high-coercivity Zr-doped α-Fe/Nd2Fe14B nanocomposite alloys

In the present work, the magnetization reversal behavior for the melt spinning (Nd0.8Ce0.2)2Fe12Co2−xZrxB (x = 0, 0.5) permanent alloys with high coercivity was investigated by analyzing the hysteresis curves and the recoil loops. Compared to the Zr-free alloy, the Zr-doped sample obtains higher magnetic properties: coercivity of Hcj = 650.5 kA·m−1, squareness of Hk/Hcj = 0.76 and maximum energy product of (BH)max = 131.0 kJ·m−3. The first-order reversal curves (FORCs) analysis was taken to identify optimal conditions of exchange coupling for the Zr-free and Zr-doped alloys. The coercivity mechanism of the α-Fe/Nd2Fe14B nanocomposite alloys was analyzed by the angular dependence of the coercive field as measured for the Zr-doped sample. The results show that the magnetic reverse process of the Zr-doped sample can be explained by the pinning model.