Dielectric properties of spinel Co3-xMnxO4 (x = 0.1, 0.4, 0.7, and 1.0) ceramic compositions

Abstract

Cobalt manganese oxides Co_3-xMn_xO₄ (x = 0.1, 0.4, 0.7, and 1.0) multi-ferroic ceramic were prepared by conventional solid state technique to understand the effect of Mn substitution at Co site on the structural and dielectric properties. Single phase polycrystalline with a linear increase in the lattice parameter ‘a’ was observed without any structural change in cubic crystal symmetry with Mn substitution. The effect of Mn substitution on the dielectric constant (ε') and loss tangent (tan) was measured over a wide temperature range (150-450 K) and frequency range (100-900 kHz). A very weak frequency dispersion and small temperature dependence was observed in ε' and tan at low temperature, however, ε' and tan display a strong frequency and temperature dependency at higher temperature. The ε' shows a ferroelectric like transition and shift to lower temperature with Mn incorporation. The behaviour of tan shows dielectric relaxation and also shifts towards lower temperature with Mn incorporation. The ceramic compositions show universal dielectric response with temperature dependent exponent factor‘s’ and which fall in Jonscher’s range.