Magnetic Properties of Gd₂Co_17-xSi_x Compounds

Effects of substituting small amounts of Si for Co on the structure and magnetic properties of Gd₂CO₁₇ compounds were studied by means of x-ray diffraction and magnetization measurements. All samples are of single phase with the rhombohedra1 Th₂Zn₁₇, type structure. The substitution 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 increasing Si concentration, being an approximately linear rate of about 4.1μB per substituted Si. The Curie temperature of Gd₂Co_17-xSi_x is found to decrease monotonously from 1213 to 651 K, as x increases from 0 to 3. X-ray diffraction measurements on magnetically aligned powders show that the easy magnetization direction of Gd₂Co_17-xSi_x compounds changes from basal plane to c-axis with increasing Si concentcation. The samples with x = 2, 3 exhibit a room temperature uniaxial anisotropy.