New insights into perovskite phase stabilization in donor–acceptor co-doped BaTiO3

This study reports, for the first time, the possibility of exploitation of the defect chemistry to suppress the hexagonal phase formation in donor–acceptor co-doped BaTiO3. Systematic Raman and electron paramagnetic resonance spectroscopic investigations have been carried out to understand the mechanism responsible for the suppression of hexagonal phase in Lanthanum and manganese co-doped BaTiO3. Stabilization of the perovskite phase is related to the donor/acceptor ratio and the doping mechanism. Suppression of the hexagonal phase is found to be facile in barium-deficient compositions, whereas in titanium-deficient compositions, coexistence of cubic and hexagonal phase is observed at [La3+] ≥ 0.02. However, in highly B-site acceptor-doped compositions, [Mn3+] ≥ 0.01, h-phase stabilization occurs irrespective of donor/acceptor ratio in both barium- and titanium-deficient compositions. This has opened up a new pathway for the synthesis of hexagonal phase-free donor–acceptor co-doped BaTiO3.