Effect of MgO Doping on the Phase Transformations of BaTiO 3

The successive phase transformations in MgO‐doped BaTiO 3 were studied. Upon MgO doping, dielectric anomalies corresponding to lower phase transformations were broadened and depressed, while an anomaly for a cubic–tetragonal transformation remained and shifted to a lower temperature. XRD peak splitting upon tetragonality of BaTiO 3 was decreased, and the peaks exhibited abnormally broadened profiles which are different from the one for cubic BaTiO 3 above T c . Raman spectroscopy revealed the existence of orthorhombic phase at room temperature for the solid solution with 0.5 mol% or more MgO. The temperature dependence of the Raman spectrum showed that orthorhombic and rhombohedral phases in MgO‐doped BaTiO 3 were stabilized at higher temperatures than pure BaTiO 3 .