Formation of core-shell structure in the BaTiO3-SrTiO3 system

When a 1-mol%-Fe2O3-added 0.67BaTiO(3)-0.33SrTiO(3) (mole ratio) powder com pact was sintered at 1380 degrees C, a core-shell structure was developed. The core phase formed via solid-state interdiffusion of barium and strontiu m ions between BaTiO3 and SrTiO3 particles. In contrast, the shell phase fo rmed via a solution-precipitation process in the presence of an Fe2O3-conta ining liquid phase. Energy-dispersive X-ray analysis showed that the core w as a strontium-rich paraelectric phase and the shell was a barium-rich ferr oelectric phase at room temperature. The core-shell structure developed in the BaTiO3-SrTiO3 system suggests the possibility of obtaining a variety of phase distributions with different Curie temperatures.