The magnetization behavior of melt-spun FeDy-B alloys

We report the salient features of the magnetization behavior of melt-spun ribbons of (Dy0.33Fe0.67)(1-x)B-x with x = 0, 0.05, 0.1 and 0.15 alloys. The temperature dependence of magnetization and low-temperature hysteresis loops were measured using a vibrating sample magnetometor during heating from 5 to 900 K, with an applied field of 50 kOe. Our results show that the addition of B seems to decrease the magnetic order and hence to decrease the exchange stiffness and the Curie temperature. Very large values of the coercive force at a low temperature of 5 K, ranging from 19 800 to 22900 Oe, was observed. The rapid increase of the coercive force at low temperatures is explained by the topological disorder due to the presence of rare earth spins distributed randomly. (C) 2001 Elsevier Science B.V. All rights reserved.