Electrical conduction mechanism and dielectric properties of the KSr0.5Fe2O4 spinel ferrite

Ferrite materials have become excellent candidates for a wide range of applications. Therefore, the solid-state reaction process was successfully employed to synthesize the KSr0.5Fe2O4 ferrite ceramic in this research. Analyzing the XRD pattern, exhibits that the sample presents a monoclinic crystalline phase, P21/n space group with lattice parameters a = 15.278 & Aring;, b = 17.664 & Aring; and c = 20.734 & Aring;. The average grain size is about 5.52 mu m. The Raman spectrum exhibits sharp, well defined bands, in agreement with a high crystallinity degree of the fabricated material, and that are observed at frequencies close to those reported previously for pure SrFe2O4. The electrical and dielectric measurements were conducted over a frequency ranging from 10 Hz to 1 MHz and a temperature varied from 313 to 533 K. The findings reveal that the AC-conductivity of the material exhibits frequency dependence consistent with Jonscher's double power law. The Nyquist plots revealed contributions from both the grains and the grain boundaries. This observation suggests that the material demonstrates a relaxation behaviour characteristic of the Cole-Cole type. The resistances at both the bulk and grain boundaries were observed to decrease with rising temperature, affirming that the manufactured material possesses a negative temperature coefficient of resistance.