The effect of Co substitution of Si on the structural and microstructural properties of GdCo9+xSi4−x

Polycrystalline samples of GdCo9+xSi4−x (x=0.0, 0.2, 0.4) were synthesized by high frequency induction melting. X-ray diffraction data were collected and crystal structure and microstructure analysis were performed using the Rietveld technique. All samples were found to have the same tetragonal crystal system with the space group I 4/mcm. They form solid solutions over the whole range of x. Decreasing the Si content from the value 4 results in an increase of the lattice parameter a and a decrease of c, both change linearly with x. Replacing Si by Co on the site 16l(2) introduces systematic changes in atomic coordinates. Crystallite size and microstrain analysis is performed along different crystallographic directions and both are found to vary anisotropically with x.