MAGNETIC-PROPERTIES OF GD2CO17-XSIX COMPOUNDS

Effects of substituting small amounts of Si for Co on the structure an d magnetic properties of Gd2Co17 compounds were studied by means of x- ray diffraction and magnetization measurements. All samples are of sin gle phase with the rhombohedral Th2Zn17 type structure. The substituti on of Si for Co leads to an approximately Linear decrease in the unit cell volume. The saturation moment at 1.5 K decreases linearly with in creasing Si concentration, being an approximately linear rate of about 4.1 mu(B) per substituted Si. The Curie temperature of Gd2Co17-xSix i s found to decrease monotonously from 1213 to 651 K, as x increases fr om 0 to 3. X-ray diffraction measurements on magnetically aligned powd ers show that the easy magnetization direction of Gd-2 Co17-xSix compo unds changes from basal plane to c-axis with increasing Si concentrati on. The samples with x = 2, 3 exhibit a room temperature uniaxial anis otropy.