Structural Transition and Microwave Dielectric Properties of ZnNb₂O₆–TiO₂Sintered at Low Temperatures

Abstract

The addition of CuO to ZnNb2O6–TiO2 significantly lowered the sintering temperature to ∼900°C in comparison to ∼1200°C for samples without CuO. The effect of CuO additions on the phase transitions and microwave dielectric properties of 0.42ZnNb2O6–0.58TiO2 has been investigated using X-ray powder diffraction and a network analyzer. The structural transition from columbite and rutile to ixiolite was influenced by both the sintering temperature as well as the amount of CuO. These influences, however, were competing. Therefore, it is assumed that the different constitutions of crystal structure of ZnNb2O6–TiO2 samples due to increase either the sintering temperature or the amount of CuO lead to considerable variation in the microwave dielectric properties. The τf was modified to ∼0 ppm/°C, as a result of the variation in phase constitutions as a function of composition.