Magnetization reversal behavior and first-order reversal curve diagrams in high-coercivity Zr-doped α-Fe/Nd 2 Fe 14 B nanocomposite alloys

In the present work, the magnetization reversal behavior for the melt spinning (Nd 0.8 Ce 0.2 ) 2 Fe 12 Co 2− x Zr x B ( 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 H cj = 650.5 kA·m −1 , squareness of H k / H cj = 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/Nd 2 Fe 14 B 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.