Compositional variation of structural, electrical and magnetic properties of Dy substituted Ni–Co spinel ferrite

Abstract

In the present work nanocrystalline dysprosium substituted Ni 0.8 Co 0.2 Fe 2-x Dy x O 4 (x = 0.00, 0.025, 0.050, 0.075 & 0.1) ferrite system was synthesized by the solution combustion method. The phase formation has been confirmed by Reitveld analysis of XRD patterns, which is a characteristic of spinel ferrite with most intense (311) peak. The bond lengths and site radii of tetrahedral and octahedral sites are found to increase with increase in Dy content. IR measurements showed two prominent bands which are common characteristics of spinel ferrite. The surface morphology shows spherical grains of increasing size with increase in Dy content. The dielectric measurements show the usual dielectric dispersion due to space charge polarization. The electrical resistivity of Ni-Co ferrites is found to increase with Dy content. This can be explained on the basis of formation of DyFeO 3 secondary phase along with spinel lattice. Complex impedance spectra show incomplete semicircles due to the high resistance values at low frequency. Magnetic measurements reveal low coercive field with increase in Dy content. Low coercive fields suggest the use of these materials in data storage and magnetic shielding devices.

Structural and Magnetic Properties of Y3+ Doped Ni–Cu–Co Ferrites Prepared by Sol–Gel Auto‐Combustion Method

“…According to the literature review, Y 3+ magnetic moment is 0 μ B . Kadam and Rajpure reported that the nickel‐cobalt ferrites, the ratio of iron ions in A site and B site is about 1:1. So before the doping, the theoretical value is about 2.4 μ B .…”