Critical Slowing Down and Elastic Anomaly of Uniaxial Ferroelectricca0.28ba0.72nb2o6crystals with Tungsten Bronze Structure
Physical review B, Condensed matter and materials physics(2014)
摘要
The ferroelectric phase transition of uniaxial Ca0.28Ba0.72Nb2O6 single crystals with a moderate effective charge disorder was investigated by Brillouin scattering to clarify the dynamic properties. In the tetragonal paraelectric phase a remarkable softening of the sound velocity of the longitudinal acoustic mode and a significant increase in the sound attenuation were observed close to the Curie temperature T-C = 527 K. The intermediate temperature T* similar to 640 K and the Burns temperature T-B similar to 790 K were determined from the temperature variation in the sound attenuation. The intense broad central peak (CP) caused by polarization and strain fluctuations due to polar nanoregions was clearly observed in the vicinity of T-C. The relaxation time determined by the CP width clearly shows critical slowing down towards T-C, reflecting a weakly first-order phase transition under weak random fields.
更多查看译文
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要