X-ray diffraction investigation of cation distribution in Cd χCu 1- χFe 2O 4 ferrite system

Abstract

Assuming the distribution of copper ions on tetrahedral (A) and octahedral (B) sites in the polycrystalline Cd χ Cu 1- χ Fe 2O 4 ( χ=0.2, 0.4, 0.6, 0.8 and 1.0) ferrite system, the theoretical intensities are calculated. Structural refinement of the diffraction pattern converges the R factor to between 0.0103 and 0.0315. Theoretical intensity ratios of (220) to (222) planes are considered, as these reflections are sensitive to cations on the A and B sites. Close agreement of the theoretical intensity ratio with the intensity ratio observed from X-ray diffraction pattern supports the occupancy of cadmium on the tetrahedral site. The cation distribution is predicted employing a new method wherein a graph of theoretical intensity is plotted against the inversion parameter for the (220) plane. The experimentally observed intensity of the same plane is then used to get an exact inversion parameter with the help of this plot. The cation distribution estimated by this method supports the cation distribution predicted by the magnetization method.