Mechanism of magnetization reversal in nanocrystalline Pr8Fe87B5

Nanocomposite Pr2Fe14B/α-Fe was prepared by melt spinning. The magnetization reversal has been examined by the initial magnetization curve, recoil curve, minor hysteresis loops, applied field dependence of coercivity and remanence, and thermal activation. Inhomogeneous pinning controls mainly the coercivity in the melt-spun ribbons. Due to the intergrain exchange coupling between soft and hard phases, the magnetization reversal is different from that in traditional permanent magnets. Thermal activation is determined by the irreversible magnetization of the hard phase.