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 Cr 3+ ions. Curie temperature ( T C ) 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.