Annealing effects on the magnetic properties of Nd₂Fe_17-xGa_x

Magnetization of Nd₂Fe_17-xGa_x, where 0≤x≤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-field 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.