Improved dielectric and relaxor behavior in LaScO3-doped K0.5Bi0.5TiO3 ceramics

Abstract

The present study reveals the effect of LaScO3 content on the structural, dielectric, and piezoelectric properties of perovskite structured (1 − x)(K0.5Bi0.5)TiO3–xLaScO3 (named as KBT–LSO) (x = 0–0.40) ceramics. A decrease in tetragonality and an increase in cubic phase fraction with LaScO3 doping were observed in Rietveld refinement of synchrotron X-ray diffraction (SXRD) data. Room temperature dielectric constant (εr) was found to improve in KBT–LSO solid solution. A continuous decrement in temperature of dielectric maxima (Tm) from 360 °C for x = 0.00 to 87 °C for x = 0.40 of LSO-doped KBT sample (at 1 MHz) was noticed. Highly diffuse dielectric anomaly and increasing relaxor behavior were observed with increased LSO doping content. The greater value of depolarization temperature (Td ~ 310 °C) compared to normal to relaxor ferroelectric transition (TF-R ~ 255 °C) for a 2% LSO-doped sample signifies a nonergodic relaxor state in the system. The impedance spectroscopy suggested improved DC resistivity with LSO incorporation in KBT lattice. The activation energies were obtained in the ranges 0.98 ± 0.03 eV to 1.50 ± 0.02 eV using Arrhenius equations which signifies the reduction in oxygen vacancies due to LSO doping. The current (I)–voltage (V) plot confirmed the decrement in room temperature DC conductivity (σDC) with LSO doping concentration. © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.