Physical and Magnetic Behaviour of Mn4+ Substitution on Ni-Mn Ferrite

The ultrafine ferrite material having general formula Ni1+xMnxFe2-2xO4; where 0.0 ≤ x ≤ 0.6 were prepared through double sintering solid state reaction technique using A.R. grade oxides of respective ions. The phase purity of all the samples was checked by X-ray diffraction technique. The X-ray diffraction pattern shows all reflections belonging to cubic spinel structure. No extra peak other than cubic spinel was observed in the X-ray diffraction pattern. Using X-ray diffraction pattern data and using Braggs law, the lattice constant was calculated for all the compositions. The lattice constant decreases linearly with Mn4+ substitutions and obeys Vegard’s law. The magnetic properties (saturation magnetization, magneton number, coercivity etc.) were investigated using pulse field hysteresis loop technique at room temperature. The values of coercivity decreases with Mn4+ content increases. The saturation magnetization and magneton number both significantly decreases with increase in Mn4+ substitution.