Structure and magnetic properties of SmCo7-xZrx alloys (x=0-0.8)

The alloys with composition of SmCo7-xZrx(x = 0 - 0.8) were synthesized and characterized in the temperature range of 10-1273 K and at fields up to 5 T. The experimental results show that a small amount of Zr substitution can contribute to a stabilization of the TbCu7 structure, and improve magneto- anisotropy H-a from 90 kOe for x = 0-180 kOe for x = 0.5 at room temperatur e, and from 140 kOe for x = 0 - 300 kOe for x = 0.5 at 10 K. It is probable that Zr may partly replace a dumbbell of Co atom pair in these alloys. The phase transition between CaCu5, TbCu7, Th2Zn17 and Ce2Ni7 at different hea t treatment conditions was also discussed. (C) 1998 American Institute of P hysics. [S0021-8979(98)29511-9].