Influence of zinc oxide addition on LnTiTaO6 (Ln = Pr, Sm and Dy) materials for dielectric resonators

LnTiTaO6 ceramics, doped with ZnO, were prepared in the solid-state ceramic route. The cylindrical samples were sintered at temperatures between 1360 and 1575 °C. The densities were measured using Archimedes method. Samples were characterized by X-ray diffraction and scanning electron microscopic methods. Microwave dielectric properties of the cylindrical samples were measured using cavity resonator method. Doping of ZnO reduced the sintering temperature. The dielectric constant (ɛr) increases for smaller doping concentrations and decreases when the doping is higher. The variation of temperature coefficient of resonant frequency (τf) decreases on smaller doping and increases on higher doping concentrations. The quality factor of all these samples are good enough for practical applications. Considerable grain growth is also observed in doped samples.