The physical origin of open recoil loops in nanocrystalline permanent magnets

The numerical simulation of the open recoil loops has been carried out using micromagnetic finite element method. By giving an example for this issue, the magnetization behaviors during the recoil processes of nanocomposite Pr2 Fe14 Bα-Fe magnets have been analyzed. It is the strong intergrain exchange coupling that results in the magnetization reversal in some hard grains during the recoil processes, which leads to the large opening of recoil loops. The magnetization reversal of α-Fe grain follows that of its neighboring hard grains. Consequently, the opening of recoil loops is enhanced due to the presence of α-Fe grains.