Humidity sensor characteristics and electrical properties of Ni–Zn–Dy ferrite material prepared using different chelating-fuel agents

Humidity sensor characteristics and electrical properties of Ni–Zn ferrite material doped with Dy were studied after synthesis via sol–gel self-combustion method. In order to obtain different micro configurations of the material reflected in different porosities, four different fuel agents were involved: citric acid, tartaric acid, cellulose and urea. XRD and XPS techniques were used to certify the composition. The influence of fuel agent and structural features on the electrical properties of ferrite sintered pellets was investigated at room temperature as a function of frequency and humidity. Because the electrical characteristics of a porous material can significantly affect by the humidity, the electrical measurements were carried out in controlled humidity environments. Conduction mechanism is explained in terms of fuel agent influence on phase composition, grain size value, cation distribution and induced strain within spinel lattice by dissolution of voluminous Dy³⁺ ions. The humidity sensors applicative characteristics of the material are highlight by analyzing the sensitivity, response and recovery times of nickel–zinc–dysprosium ferrite used as active material.