Crystal structure and related properties of manganese-doped barium titanate ceramics

The influence of manganese on the crystallographic phase and the microstruc ture of BaTi1-xMnxO3 ceramics (0 less than or equal to x less than or equal to 0.05) is investigated. The crystal structure at room temperature change s from tetragonal to hexagonal between x = 0.005 and 0.017, which causes a drastic change in the microstructure. The Jahn-Teller distortion caused by the Mn-Ti(3+) ions is pro posed as the driving force for the phase transiti on. Annealing of the as fired samples in both a reducing and oxidizing atmo sphere restores the tetragonal phase, which is accompanied by a change in t he microstructure based on the percentage of tetragonal phase.