Structure and electrical properties of Co_0.5Cd_xFe_2.5-xO₄ ferrites

We have studied the Cd ion doping effects in cobalt ferrite using X-ray diffraction (XRD), dielectric and impendence spectroscopy at room temperature. X-ray diffraction analysis indicates that all the samples exhibit a single phase nature with cubic spinel structure. The dielectric constant ε′, ε″, loss tangent tan δ and ac conductivity σ_ac have been studied as a function of frequency and composition. It is observed that doping of the Cd ions increases ε′, ε″, tan δ and σ_ac up to 20% after that it start decreasing with further doping. The dielectric properties and ac conductivity in studied samples have been explained on the basis of space charge polarization according to Maxwell and Wagner's two-layer model and the hoping between adjacent Fe²⁺ and Fe³⁺ as well as the hole hopping between Co³⁺and Co²⁺ ions at B-sites. The complex impedance analysis used to separate the grain and grain boundary of the system Co_0.5Cd_xFe_2.5-xO₄.