Annealing effects on the magnetic properties of Nd2Fe17-xGax

Magnetization of Nd2Fe17-xGax, where 0 less than or equal to x less than or equal to 3, has been measured at temperatures between 5 and 300 K and in fields between 0 and 50 kOe. These samples have the rhombohedral Th2Zn17 structure. Magnetization studies at 5 K indicate that the saturation magnetization decreases with increasing Ga concentration while at 300 K it increases for x > 0 reaching a maximum at x = 1, and decreases for x > 1. Samples annealed for different times are found to have different magnetization for the same value of x. The low-held magnetization measurements show irreversible behavior which is a reflection of hysteretic effects in this system. The peak in the magnetization shifts to higher temperatures upon increasing the Ga amount due to the increase in the Curie temperature. (C) 2000 Published by Elsevier Science B.V. All rights reserved.