EFFECTS OF GA SUBSTITUTION IN Y2FE17 COMPOUNDS ON THE MAGNETOCRYSTALLINE ANISOTROPY

X-ray diffraction patterns of Y2Fe17-xGax show that the samples prepar ed with 0 less than or equal to x less than or equal to 7.5 are single phase having the hexagonal Th2Ni17-type structure and/or the rhombohe dral Th2Zn17-type structure. The substitution of Ga for Fe in Y2Fe17 l eads to a linear increase of the unit cell volume and a linear decreas e of the saturation magnetization. The Curie temperature T-C is found first to increase with increasing gallium content n, attains a maximum value of about 540 K between x = 3 and 4, and then decreases monotoni cally. X-ray diffraction measurements on magnetically aligned powder s amples of Y2Fe17-xGax reveal a change in the easy magnetization direct ion from easy plane to easy c axis with increasing Ga concentration. T he samples with x greater than or equal to 7.0 have a uniaxial magneto crystalline anisotropy at room temperature.