Investigations on the Magnetic Properties of High-Coercivity (Nd(1-x)Fe(x))90Al10 Bulk Amorphous Alloys

Bulk rods with diameters up to 3 mm prepared by suction casting and respectively mould casting and melt-spun amorphous ribbons with thicknesses in the range 25 - 150 micrometers with compositions Nd(90-x)Fe(x)Al10 (x = 35; 40; 45; 50) were investigated by XRD, DSC and magnetic measurements in the temperature range 5 - 600 K. The microstructure and magnetic properties are strongly dependent on the cooling rate, preparation process and Fe content. The large values of the coercive field, which amount to 320 kA/m in the as-cast state as well as the increase with decrease of the temperature and cooling rate result from the formation of very small metastable or nonequilibrium magnetic clusters.