Study of structural and magnetic properties of Cr substituted Li-Zn mixed ferrites

Abstract

The effects of Crsubstitution on the structural, electrical, elastic and magnetic properties of Li0.3CrxZn0.4Fe2.3-xO4 (where x = 0.0, 0.1, 0.3 and 0.5) nominalcompositionshave been investigated along with the microstructural features. All the compositions have been sintered at~1100°C.The crystal structure of the synthesized samples has been observed with an x-ray diffraction technique andit is found to be a single-phase cubic spinel structure. The lattice constant decreases from 8.385 to 8.355Åwith an increase in Cr content. Fourier transforms infrared absorption bands studies have shown the two main absorption bands. The bulk modulus (B), rigidity modulus (G), Poisson’s ratio (σ), and Pugh's ratio (B/G) have also been calculated for all the samples.Pugh's ratio (B/G) lies in the range from 1.86 to 1.93.This indicates that the investigated samples are in an isotropic elastic nature.The microstructural study demonstrates that the grain growth of the Li-Zn ferrites is strongly dependent on Cr content. The average grain size is found to be larger at x = 0.1, which could be attributed to the densification of the sample. The magnetic properties have been observedand it is seen that the saturation magnetization reduces from 80.3 to 46.4 emu/g as the content of Cr increases from x = 0.0 to 0.5. This could be attributed to the weakened of exchange interaction between the spinel sub-lattices.The complex permeability measurement shows that the initial permeability is found to be larger at x = 0.1, which could be ascribed to the larger grain size along with the densification of the samples. The dielectric constant has been studied along with ac electrical conductivity. The ac electrical conductivity is found to larger for Li0.3Cr0.1Zn0.4Fe2.2O4(at x=0.1).The Cole-Cole plot shows that the electrical conduction occurs due to the contribution of both the grain and grain boundary.