HIGH-FREQUENCY DIELECTRIC BEHAVIOR OF INDIUM AND CHROMIUM SUBSTITUTED Mg-Mn FERRITES

Dielectric properties such as DC resistivity (rho), dielectric constant (epsilon) and dielectric loss factor (tan delta) have been measured for Mg0.9Mn0.1InxFe2-xO4 and Mg0.9Mn0.1CryFe2-yO4 at room temperature. The composition dependence of rho, epsilon and tan delta and the frequency dependence of epsilon and tan delta presented in this paper. The resistivity increases while the dielectric constant decrease with increasing concentrations of indium and chromium ions. The dielectric loss factor at 100 kHz increase with composition for the samples 0.1 <= x <= 0.9 and 0.1 <= y <= 0.7. The dielectric constant for a given sample decreases with increasing frequency showing the normal dielectric behavior. The values of dielectric loss factor have been found to increase with frequency for the samples corresponding to x or y = 0.1 to 0.5; while other samples showed abnormal dielectric behavior. The observed variation in rho are explained by Verwey's hopping mechanism while the variation in epsilon and tan delta with composition and frequency are explained by space charge polarizaion using Koop's theory. Higher values of DC resistivity and low dielectric losses suggest that the prepared materials have great potential for microwave and high-frequency applications.