SrTiO_3晶体铁弹相变的研究

Ferroelastic phase transition of SrTiO_3

利用慢度曲面法研究SrTiO3晶体的铁弹相变.画出了SrTiO3晶体在发生铁弹相变过程中一些温度下的慢度曲面,发现SrTiO3晶体在108.2 K时发生了铁弹相变,声学模软化的方向是101.进一步的研究表明该相变与弹性劲度系数11 12密切相关,晶体的对称性由立方相Oh群变到四方相D4h群.以上结果均与实验相吻合.

The slowness surface method is used to study the ferroelastic phase transition of SrTiO3 crystal. The slowness surfaces of SrTiO3 have been drawn at some temperatures, which shows that the ferroelastic phase transition of SrTiO3 crystal occurs at 108.2 K. The softening direction of the acoustic soft mode is found to be in 101. Furthermore, we have found that the phase transiton is closely related to the elastic stiffness coefficients11 12. The symmetry changes from Oh group of cubic system to D4h group of tetragonal system. The results agree with the experimental results.