Brillouin Scattering Studies of the Uniaxial Ferroelectric Phase Transition in TGS and TGSe
Brillouin Scattering Studies of the Uniaxial Ferroelectric Phase Transition in TGS and TGSe
复制标题
TGS 和 TGSe 中单轴铁电相变的布里渊散射研究
DOI：
10.1143/jpsj.40.1659
复制
发表时间：
1976
影响因子：
1.7
通讯作者：
I. Tatsuzaki
中科院分区：
文献类型：
--
作者：
T. Yagi;M. Tokunaga;I. Tatsuzaki
在（100）面内观察了三甘氨酸硫酸盐（TGS）及其类质同晶硒酸盐（TGSe）晶体在三种纵向或准纵向声子矢量q取向情况下的布里渊谱：（1）q // c轴，（2）q // B轴和（3）q偏离B轴5°。频率偏移和谱宽的温度依赖性在Tc附近表现出显著的各向异性。在情况（1）中，宽度变为最大值时的温度向比Tc低的温度移动，Tc是同时通过介电常数的测量确定的。极化弛豫时间是从这个温度变化确定使用的唯象关系。在情况（2）和情况（3）中，反常的减少被解释为在铁电相变中特有的长程偶极-偶极相互作用的退极化场效应。
The Brillouin spectra of the ferroelectric triglycine sulfate (TGS) and its isomorphous selenate (TGSe) crystals have been observed in three cases of orientations of the longitudinal or quasi-longitudinal phonon vector q ; (1) q // c -axis, (2) q // b -axis and (3) q deviates 5° from b -axis in the (100) plane. The temperature dependence of both the frequency shift and the spectral width shows a remarkable anisotropy near T c . In the case (1) the temperature at which the width becomes maximum shifts to the lower temperature than T c which has simultaneously been determined by an accompanied measurement of dielectric constant. The polarization relaxation time is determined from this temperature shift using the phenomenological relation. In the case (2) and the case (3), the decrease in the anomaly is explained as the depolarization field effect of the long range dipole-dipole interaction which is characteristic in the ferroelectric phase transition.