Anomalous longitudinal acoustic phonon and elastic constant in potassium alum KAl(SO4)2•12H2O single crystal studied by Brillouin spectroscopy

被引：5

作者：

Ko, Jae-Hyeon ^{[1
]}

Oh, Soo Han ^{[1
]}

Lee, Kwang-Sei ^{[2
]}

机构：

[1] Hallym Univ, Nano Convergence Technol Ctr, Sch Nano Convergence Technol, Chunchon 24252, South Korea

[2] Inje Univ, Ctr Nano Mfg, Dept Nano Sci & Engn, Gimhae 50834, South Korea

来源：

JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS | 2020年 / 140卷

基金：

新加坡国家研究基金会;

关键词：

Potassium alum; Brillouin scattering; Acoustic phonon; Elastic constant; Orientational disorder; ORIENTATIONAL DYNAMICS; PHASE-TRANSITION; RAMAN-SPECTRA; ALPHA-ALUMS; SCATTERING; RELAXATION; VIBRATIONS; GLASSY; IONS;

D O I：

10.1016/j.jpcs.2020.109364

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

The longitudinal acoustic phonon propagating along the [100] direction in a potassium alum KAl(SO4)(2)center dot 12H(2)O single crystal from 297 to 77 K has been studied on the basis of Brillouin light scattering. On cooling, inverse sigmoid-shaped hardening of the Brillouin shift (and the associated elastic constant C-11) was observed. An anomalous hump in the full-width at half-maximum (FWHM) appeared in the vicinity of 233 K. These anomalous changes in the acoustic properties were wholly unexpected, and may be attributed to coupling between the longitudinal acoustic phonon waves and the orientational degree of freedom of sulfate anions in the crystal. The temperature dependence of the relaxation time of the relevant relaxation process was derived on the basis of a single-relaxation-time approximation, which showed an increase in the relaxation time upon cooling, indicating dynamic slowing down.

引用

页数：5

共 41 条

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