Studies on the solid solution of Mn in BaTiO3

BaTi1-xMnxO3 solid solutions with 0 < x < 0.04 were synthesized in reducing atmosphere (P-O2 < 10(-9) Pa) and in air at 1350 degreesC for 2h. The effect of Mn ions with different valences on the crystal structure of BaTiO3 was studied by the room-temperature Raman scattering, electron spin resonance (ESR) and X-ray powder diffraction analyses. The crystal structure of the solid solution was analyzed to determine the change of its lattice parameters. It was found that in a reducing atmosphere, Mn2+ ions promoted the tetragonal-to-cubic transformation, as both a contraction of c-axis and an extension of a-axis were observed with an increase in Mn content. In contrast, Mn ions in the air-synthesized samples promoted the tetragonal-to-hexagonal transformation. The formation of the hexagonal phase was accompanied by a strong extension of the c-axis of the tetragonal phase from 4.032 Angstrom to 4.042 Angstrom. This was attributed to Jahn-Teller distortions caused by Mn3+ ions.