A study on the structure, dielectric and piezoelectric properties of BaAl0.5Nb0.5O3 modified K0.5Na0.5NbO3 ceramics

Abstract

Polycrystalline solid-solution (1-x) K0.5Na0.5NbO3 - x BaAl0.5Nb0.5O3 (abbreviated as (1-x) KNN-xBAN) with x = (0 - 0.05) were synthesized via the conventional solid-state reaction route.The effects of BAN doping on the crystal structure, dielectric and piezoelectric properties of KNN were studied. The room temperature x-ray diffraction analysis suggested a structural transformation from orthorhombic to a pseudo-tetrgonal with increasing BAN content. Temperature-dependent dielectric measurements showed the increase in diffuseness of phase transitions. Interestingly, temperature corresponding to tetragonal to cubic phase transition remained almost constant in all samples. A modest increase in room temperature piezoelectric charge coefficient (d33) from 80 pC/N (for pure KNN) to 95 pC/N for the composition corresponding to x = 0.02. © 2020 American Institute of Physics Inc.. All rights reserved.