Effect of temperature and frequency on the studies of structural and dielectric behavior of ABO3 type orthorhombic perovskite

Abstract

Lead-free sodium niobate (NaNbO3) ceramics is prepared via conventional solid state reaction technique at sintering temperature 1150 °C for 4 h. The structural and surface morphology of the sample has been done by using X-ray diffraction and Field emission scanning electron microscopy (FE-SEM), respectively. The XRD study of NaNbO3 (NN) sample confirmed the formation of single phase with orthorhombic crystal structure. The surface micrographs of NN sample indicates the formation of grains with clear grain boundaries and orthorhombic shape. The detailed investigation of dielectric properties of NN ceramics are done in wide frequency range (100 Hz – 1 MHz) at various temperatures (250 °C – 330 °C). The magnitude of real dielectric constant (e′) and dielectric loss (tan δ) are strongly dependent on temperature and frequency. The analysis of frequency dependent conductivity reveals that the conduction done by grain boundaries and grains, both. The impedance study reveals that the negative temperature coefficient of resistance (NTCR) behavior and time relaxation in NN ceramic.