Magnetocapacitance in Dy-doped ni ferrite

Ferromagnetic and ferroelectric characteristics of Dy substituted nickel ferrite, NiO center dot Fe1.925Dy0.075O3, were investigated. The material formed in the cubic inverse spinel phase with a small amount of DyFeO3 as the additional phase. A small distortion of the cubic lattice was observed upon the substitution of Fe by Dy (in the B site). Substitution of Dy for Fe caused a decrease in the saturation magnetization and Curie temperature of the nickel ferrite. Magnetocapacitance of -4% was observed in NiO center dot Fe1.925Dy0.075O3 although the magnetostriction has not significantly changed with Dy substitution. The (high) dielectric constant with frequency is seen to reveal the dispersion in relaxation times.