Phase characteristics, microstructure, and electrical properties of (1-x)BaZr<inf>0.2</inf>Ti<inf>0.8</inf>O<inf>3</inf>-(x)(Ba<inf>0.7</inf>Ca<inf>0.3</inf>)<inf>0.985</inf>La<inf>0.01</inf>TiO<inf>3</inf> ceramics

Abstract

© 2019 Elsevier Ltd and Techna Group S.r.l. In this study, (1-x)BaZr0.2Ti0.8O3-(x)(Ba0.7Ca0.3)0.985La0.01TiO3 ((1-x)BZT-(x)BCLT) ceramics, where x = 0.3, 0.4, 0.5, and 0.6, were prepared employing a conventional solid-state sintering technique. X-ray diffraction patterns and dielectric measurements indicated three phase regions at room temperature, including a single rhombohedral (x = 0.3), a phase coexistence of rhombohedral and tetragonal (x = 0.4), and a single tetragonal structure (x ≥ 0.5). X-ray photoemission spectra at the surface of ceramics confirmed the oxidation state of Ba2+, Ca2+, Ti4+, and Zr4+ ions. Upon BCLT addition, the reduction of the average grain size and the presence of the tetragonal structure significantly affected the dielectric, ferroelectric, and piezoelectric properties of these ceramics. With these results, the composition x = 0.3 showed maximum εr′ and εm′, whereas the composition x = 0.5 showed maximum Pr, Ec, d33, kp, and d∗33 factors. These results suggest a new phase diagram for the (1-x)BZT-(x)BCLT system, which could be tuneable by BCLT concentration and might be useful as an alternative material in dielectric, ferroelectric, and piezoelectric devices.