Magnetization Reversal Processes in Pr-Fe-B-type Nanocrystalline Magnets

The magnetization reversal processes in magnets derived from rapidly solidified $Pr_{9}Fe_{52}Co_{13}Zr_{1}Nb_{4}B_{21}$ alloy samples were studied by analysis of minor hysteresis loops and recoil curves. The studies were carried out on suction-cast 1 mm diameter rod, 1 mm thick plate, 3 mm outer diameter (o.d.) tube and melt-spun ribbon samples subjected to annealing at 983 K for 5 min. The X-ray diffraction analysis has shown multiphase constitution of the samples. Structural and magnetic studies indicated that the initial state of microstructure and phase composition affects the magnetization reversal processes in annealed samples due to a variation of microstructure in samples of various shapes. Magnetic studies allowed estimation of the mean values of nucleation and pinning fields that control the magnetization reversal processes.