Effect of cation distribution on the structural and magnetic properties of nickel substituted nanosized Mn–Zn ferrites prepared by co-precipitation method

Nano particles of Mn(0.5–x)NixZn0.5Fe2O4 (x=0.0, 0.1, 0.2, 0.3) have been synthesized by chemical co-precipitation method. The lattice constant and distribution of cation in the tetrahedral and octahedral sites have been deduced through X-ray diffraction (XRD) data analysis. The lattice constant (Å) for all Mn/Ni concentration is found to be less than that for the corresponding bulk values. X-ray intensity calculations indicate that there is deviation in the normal cation distribution. Magnetization decreases with increasing Ni concentration except for x=0.3, where it shows increasing trend. This is due to migration of Fe3+ ions from B-site to A-site, which reduces the B–B coupling and there by the spin canting in the B sublattice. The Curie temperature was found to decrease with increase in nickel concentration except for x=0.3, where it shows a rise. Coercivity is very low and is found to be inversely proportional to the grain size.