Electrical Conductivity and Dielectric Properties of Lead‑Free Perovskite: Ca0,08Na0,92Sn0,08Nb0,92O3 Ceramic

Abstract

The physical properties of the Multiferroïc Ca 0,08 Na 0,92 Sn 0,08 Nb 0,92 O 3 ceramic were investigated by the X-ray Diffraction (XRD), morphology, piezoelectric, dielectric and electrical measurements. The X-ray diffraction patterns at room temperature revealed a single-phase perovskite crystallizing with quadratic P4mm group symmetry. The microstructural analysis shows the homogeneously grainy morphology of the compound with grain sizes varying from 2nm to 5.5nm. The piezoelectric responses were investigated as a function of temperature and frequency. The thermal evolution of the relative dielectric permittivity (ε'r) exhibited a very important peak with no frequency dependence, which revealed a classical ferroelectric behavior. So as to investigate the electrical transport, a complex impedance spectroscopy is highlighted. With the Debye theory-based analysis and a series of Arrhenius relations, the Nyquist plots are well suitable to an equivalent circuit model. Moreover, the conductivity spectrum exhibits the two phase transitions detected in the dielectric measurements.