Impulsive stimulated Brillouin scattering studies of the ferroelectric phase transition in tris-sarcosine calcium chloride.
Impulsive stimulated Brillouin scattering studies of the ferroelectric phase transition in tris-sarcosine calcium chloride.
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三肌氨酸氯化钙铁电相变的脉冲受激布里渊散射研究。
DOI：
10.1103/physrevb.39.9437
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Nelson
中科院分区：
文献类型：
--
作者：
Cheng;Nelson
使用散射角为 23.78 和 6.03 的“脉冲”受激布里渊散射，研究了沿着三肌氨酸氯化钙在其铁电相变附近的所有三个主轴的纵向声声子异常。在两个阶段都观察到平均场行为的对数校正。超声波的动态色散分析、布里渊散射和目前的结果证实了具有基本弛豫时间 τ 0= 5.5× 10− 12 s K 的朗道-哈拉特尼科夫阶参数动力学。沿着极轴的异常声学行为被确定是由弱去极化场和接近三临界点引起的。能量弛豫被认为是沿着极轴的尖锐声学异常的根源，这种异常在超声波研究中观察到，但在探测更高声频的光学实验中却没有观察到。
The longitudinal acoustic-phonon anomalies along all three principal axes of tris-sarcosine calcium chloride near its ferroelectric phase transition were studied using ‘‘impulsive’’stimulated Brillouin scattering with scattering angles of 23.78 and 6.03. Logarithmic corrections to mean-field behavior are observed in both phases. Dynamic dispersion analysis of ultrasonic, Brillouin scattering, and the present results confirmed Landau-Khalatnikov order-parameter dynamics with an elementary relaxation time τ 0= 5.5× 10− 12 s K. The unusual acoustic behavior along the polar axis is determined to result from a weak depolarization field and the proximity to a tricritical point. Energy relaxation is believed to be the source of sharp acoustic anomalies along the polar axis which are observed in ultrasonic studies but not in optical experiments which probe higher acoustic frequencies.