Structural refinement and impedance spectroscopy of lead-free (K,Na) (Nb)O3-xBiErO3 piezoelectric ceramics

The structural and electric transport properties of BiErO3-(KNa)NbO3 composite ceramics were investigated in this study. The structural changes have been studied quantitatively through refinement techniques around the phase transition. The presence of binary phase regions was depicted through Le-Bail and Rietveld refinement techniques in the compositional range x = 0.5–1.0%. Electrical transport properties of (K,Na) (Nb)O3-xBiErO3 for all compositional range were probed at room temperature. The influence of grains and grain boundaries was perceived on electrical properties by employing impedance spectroscopy (IS) in the frequency range from 20 Hz to 2 MHz for given samples. The ceramic samples presented non-Debye type relaxation phenomenon in impedance spectroscopic plots, trailed by thermally activated process, may be correlated to hopping phenomena.