A Relaxational Central-Mode in KDP
A Relaxational Central-Mode in KDP
复制标题
KDP 中的松弛中心模式
DOI：
10.7567/jjaps.24s2.923
复制
发表时间：
1985
影响因子：
1.5
通讯作者：
T. Yagi
中科院分区：
文献类型：
--
作者：
A. Sakai;T. Yagi
本文用法布里-珀罗干涉仪和双单色仪组成的高分辨光散射系统，在0 ~ 10 cm ~（-1）的频率范围内研究了KDP的铁电相变动力学。在x（yx）y几何中观察到的光谱显示出在相变温度Tc附近增长的宽中心分量。利用Debye型极化率函数分析了该分量，该函数包括极化弛豫时间τ和静态极化率χ（0）。发现τ存在临界慢化，χ（0）服从Curie-Weiss定律.中心分量的起源被分配到波动的极化，成为发散附近Tc。极化的有序-无序机制很好地解释了KDP的相变。
The dynamics of the ferroelectric phase transition of KDP has been studied by the use of a high-resolution light-scattering system, which is composed of a Fabry-Perot interferometer and a double monochromator, in the frequency range from 0 to 10 cm-1. The spectra observed in the x(yx)y geometry show a broad central component which grows up near the phase transition temperture Tc. This component is analyzed by using a Debye-type susceptibility function which includes the polarization relaxation time τ and the static susceptibility χ(0). It is found that τ shows a critical slowing down and χ(0) obeys the Curie-Weiss law. The origin of the central component is assigned to fluctuating polarization which becomes divergent near Tc. The phase transition in KDP is well explained by an order-disorder mechanism of the polarization.