Strain related curie temperature and improved piezoelectric properties of lead-free (1-x)Ba(Sn,Ti)O3-x(Ba,Ca)TiO3 ceramics

In this study, as a BaSnTiO3 structure based material, (1-x)Ba(Sn,Ti)O-3-x(Ba,Ca)TiO3 piezoelectric ceramic was investigated for piezoelectric applications. Even though high piezoelectric properties, low Curie temperature is the obstacles for the applications. To increase Curie temperature of BaSnTiO3 material, (Ba,Ca)TiO3 ceramic was added. (Ba,Ca)TiO3 ceramic has shorter a-parameters compared with that of BaSnTiO3 ceramics, while c-parameter remains similar values of 4.02 angstrom. Due to the increased strain of (1-x)Ba(Sn,Ti)O-3-x(Ba,Ca)TiO3, the Curie temperature can be controlled. Also, we have analyzed the structural and piezoelectric properties of a (1-x)Ba (Sn,Ti)O-3-x(Ba,Ca)TiO3 system for application to an energy harvesting system. (1-x)Ba(Sn,Ti)O-3-x(Ba,Ca)TiO3 ceramics with x = 0.4, 0.5, 0.55, 0.6, and 0.7 were synthesized and analyzed at sintering temperatures from 1455 to 1505 degrees C. We investigated the piezoelectric charge coefficient and P-E hysteresis loops. Results showed that the optimized composition of (1-x)Ba(Sn,Ti)O-3-x(Ba,Ca)TiO3 ceramics was x = 0.55, sintered at 1480 degrees C. As lead-free piezoelectric ceramics, it is expected that (1-x)Ba(Sn,Ti)O-3-x(Ba,Ca)TiO3 ceramics will be promising candidates for various applications.