Effect of tantalum on the temperature dependent electrical characteristics of NaNb1−xTaxO3 (0.0 [formula omitted] x [formula omitted] 0.3) ceramics between 400 and 560 °C

Abstract

NaNb1−xTaxO3 (x = 0.0, 0.1, 0.2 and 0.3) (NT0, NT1, NT2 and NT3) ceramics are synthesized by conventional solid state reaction technique at high sintering temperature 1150 °C for 4 h. The crystallinity and surface morphology are studied by X - ray diffraction (XRD) and Field emission scanning electron microscopy (FE-SEM) at room temperature, respectively. XRD analysis of Ta ion doped sodium niobate ceramics confirms the formation of single phase with orthorhombic symmetry. In FE - SEM analysis, the effect of tantalum (Ta) ion on the grain growth of NT ceramics is clearly noticeable. With increasing the amount of Ta ion in NT ceramics, size of grains get diminished. The dielectric and impedance behavior of NT material are studied as a function of frequency (100 Hz - 5 MHz) at selected temperature (400 °C - 560 °C). The maximum value of real permittivity (ε') is obtained in NT3 ceramics at 560 °C temperature. The impedance analysis of NT ceramics confirms that the relaxation peaks shift toward higher frequency with a rise in temperature. Such type of change in relaxation peak is attributed to the temperature dependent time relaxation phenomenon present in material.