Effects of sintering temperature on the microstructure, electrical and magnetic characteristics of copper-zinc spinel ferrite with possibility use as humidity sensors

Abstract

In this paper was investigated the effect of sintering temperature on a copper-zinc spinel ferrite, Cu0.5Zn0.5Fe2O4, synthesised by using a sol-gel self-combustion method, as material with possible to application in the field of humidity sensors. In order to highlight the influence of temperature treatment on the structure, electrical and magnetic properties, the powders of ferrite were annealed at various temperatures: 850 °C, 900 °C, 950 °C, 1000 °C and 1050 °C. For the analyzed samples, the X-ray diffraction investigations have revealed the phase composition and the average crystallite size. By using techniques scanning electron microscopy (SEM) and atomic force microscopy (AFM) were find the influence of the sintering temperature on some parameters like the porosity, homogeneity, shape and size of the crystallites. We have also investigated the temperature variation of the electrical conductivity, relative magnetic permeability and relative permittivity variation with frequency at room temperature. Finally, we analyzed the time response, variations of electrical conductivity and relative permittivity for various humidity levels and the perspectives of applicability copper-zinc spinel ferrite as humidity sensor.