Influence of oxygen vacancies and electrical properties in Ba0.92Ca0.08Zr0.05Ti0.95O3 ceramics through the co-doping of La3 + and Tm3+ ions

Abstract

Barium calcium zirconate titanate (BCZT)-based piezoelectric ceramics, which are modified with rare earth elements, are one of the candidates for replacing lead-based piezoelectric ceramics. In this study, the BCZT-0.8 %La-xTm ceramics were prepared using the sol-gel method. The effects of varying Tm3+ ions contents on the dielectric, ferroelectric, and piezoelectric properties of ceramics were investigated and the influence mechanism was discussed. Results showed that La3+ and Tm3+ ions co-doping can affect the motion of domains and domain walls by adjusting oxygen vacancy concentrations and microstructure, which is the main reason for the various electrical properties of ceramics. Especially when the Tm3+ ions content is 2 %, many oxygen vacancies would generate, which is due to Tm3+ ions replace to B-site cations. These oxygen vacancies would produce pinning effect for the domains, which would reduce the electrical properties of the ceramics. When Tm3+ ions content was 0.7 %, the ceramics showed excellent dielectric constant (ԑr = 9941.6), remnant polarisation (Pr = 28.93 μC/cm), and piezoelectric constant (d33 = 181 pC/N). The results have some reference value for enhancing the electrical properties of BCZT piezoelectric ceramics using elements co-doping.