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 Ha from 90 kOe for x=0–180 kOe for x=0.5 at room temperature, 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 heat treatment conditions was also discussed.