Cation distribution by Rietveld, spectral and magnetic studies of chromium-substituted nickel ferrites

Ultrafine crystals of chromium-substituted nickel ferrite were prepared by wet chemical co-precipitation method using sulphates of respective metal ions. Formation of these materials has been confirmed by X-ray powder diffraction method. The fine crystal nature of these materials is evidenced from scanning electron microscope (SEM). Cation distribution has been investigated using X-ray diffraction technique. Cation distribution indicates that chromium occupy octahedral site for all the values of composition x. The saturation magnetization and magneton number both are decreasing with increase of chromium concentration x. The decrease in saturation magnetization and magneton number is attributed to the substitution of the Cr3+ ions. Curie temperature (TC) from susceptibility plot is found to decrease with Cr concentration x. Curie temperature of all the compositions are also obtained theoretically and it agrees with observed Curie temperature.