Characterization of Zn doped MgTiO3 ceramics: an approach for RF capacitor applications

Abstract

In the present study the effect of Zn substitution on densification, microstructure, microwave and broad band dielectric properties of MgTiO3 ceramics were investigated. The (Mg1−x Zn x )TiO3 (x = 0.01–0.07) ceramics have been prepared by the conventional solid-state reaction method. The sintering conditions were optimized to obtain the best dielectric properties with maximum relative densities. The microwave dielectric properties are heavily influenced by the amount of x concentration. The optimum dielectric properties of e r ~ 17.34, Q × f o ~ 274 THz, τ f ~ -40.3 ppm/oC is obtained for (Mg0.95Zn0.05)TiO3 ceramics sintered at 1275 °C. The broad band dielectric properties of (Mg0.95Zn0.05)TiO3 ceramics were measured in the frequency range of 1–100 MHz, and temperature range of 133–483 K. Interestingly, the broad band dielectric properties show relaxation behaviour with frequency. The higher temperature dielectric spectrum of (Mg0.95Zn0.05)TiO3 (MZT) ceramics displayed a distinct dispersion, which is shifting towards a lower frequency side. The observed dielectric relaxation behavior is analyzed using Cole–Cole plot. Furthermore, voltage dependent capacitance behavior at different frequencies is studied for the MZT sample, and it’s interesting to note that the capacitance is stable with the variation in voltage. The electrical conductivity study is carried out as a function of frequency and temperature for MZT sample and the activation energy is calculated by using Arrhenius equation, which is found to be 0.07 eV at 10 MHz. The obtained dielectric response of MZT ceramics are suitable for dielectric resonator and type-1 RF capacitor applications.