Both BaTiO3 and CaTiO3 have perovskite structure, but the former belongs to tetragonal system and the latter is cubic at room temperature.
Combining BaTiO3 and CaTiO3 forms the BaTiO3-based solid solution (BaTiO3(s.s.)),
the CaTiO3-based solid solution (CaTiO3(s.s.)) or the BaTiO3(s.s.) and CaTiO3(s.s.) two phase mixed structures, according to the composition (Fig. 1).