Abstract Acoustic anomalies of relaxor ferroelectric Na1/2Bi1/2TiO3 single crystals were investigated over a wide temperature range from −196 °C to 900 °C by using Brillouin spectroscopy. The longitudinal sound velocity, the acoustic absorption coefficient and the elastic constant C11 were determined for the acoustic phonon mode propagating in the [100] direction. Two acoustic anomalies, weaker ones at the cubic-tetragonal phase transition temperature of ~540 °C and more pronounced ones at temperatures near 315 °C near the dielectric maximum temperature, were investigated and discussed in relation with the relevant order parameters coupled to the acoustic waves. The relaxation dynamics in the cubic phase were studied based on the flattening of the mode frequency and the half width, which was observed for the first time, and a modified Arrhenius law.

中文翻译：

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利用布里渊光谱研究弛豫铁电 Na1/2Bi1/2TiO3 单晶的声学异常和弛豫动力学

摘要 利用布里渊光谱法研究了弛豫铁电体 Na1/2Bi1/2TiO3 单晶在 -196 °C 至 900 °C 的宽温度范围内的声学异常。纵向声速、吸声系数和弹性常数 C11 是为在 [100] 方向上传播的声学声子模式确定的。研究和讨论了两种声学异常，即在约 540 °C 的立方-四方相变温度下较弱的异常和在接近介电最高温度的 315 °C 附近的温度下更明显的异常，并与耦合到声学的相关阶参数相关波浪。基于首次观察到的模式频率和半宽的平坦化，研究了立方相中的弛豫动力学，