Structural, electrical and transport phenomena of Co ferrite substituted by Cd

Abstract

A series of samples of Co 1− x Cd x Fe 2O 4 ( x=0, 0.1, 0.3, 0.5, 0.7and 0.9) were prepared by the usual ceramic technique and sintered at 1473 K for 6 h. The X-ray analysis shows the existence of single phase spinel structure with the increase of lattice parameter and density with increasing Cd contents whereas the porosity decreases. The DC electrical conductivity increases with increasing temperature. It is also increased by increasing Cd content and reaches maximum at x=0.7 at which the activation energy for conduction becomes minimum. The transition temperature T c shifts to a higher value as Cd content increases. The thermoelectric power α is converted from a positive value for Co ferrite (hole) to a negative value for the mixed ferrite Co 1− x Cd x Fe 2O 4. The activation energy for mobility E μ is nearly equal to E σ and the thermoelectric power α is nearly constant with the variation of temperature which make together a strong reason for the presence of hopping condition mechanism.