Structural and magnetic properties of Bi substituted nickel ferrite

Polycrystalline Ni1-xBixFe2O4 (x = 0.00, 0.05 and 0.10) are prepared by a solid state method. The crystal structure, and magnetic properties are investigated using XRD, Raman and VSM magnetometer. The material formed in the cubic inverse spinel phase without any impurity from XRD. A small distortion of the cubic lattice is observed upon the substitution of Ni by Bi in the A site. The lattice parameter (a) changes non monotonically, first increases then decreases with Bi doping content. From Raman measurements, Raman modes match with the typical modes of cubic inverse spinel ferrite structures belonging to the Fd (3) over barm space group. The gradual shifts in wave numbers indicate that the Bi3+ substitutes for Ni3+ at the A-site. The M-s Values of the Ni1-xBixFe2O4 compounds are found to decrease with increasing for 5% doped Bi sample and again increase for 10% Bi doped sample. The Curie temperature T-C values of Ni1-xBixFe2O4 are 871, 875 and 885 K, for x = 0.0, 0.05 and 0.1 respectively. It is important to note that the TC value increases in Bi-substituted nickel ferrites compared to pure nickel ferrite. (C) 2020 Elsevier Ltd. All rights reserved.