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Brillouin study of the hexagonal—orthorhombic phase transition in LiKSO 4
Author(s) -
Young P. W.,
Katiyar R. S.,
Scott J. F.
Publication year - 1984
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250150511
Subject(s) - orthorhombic crystal system , phase transition , brillouin zone , raman spectroscopy , hexagonal crystal system , potassium niobate , phase (matter) , lithium (medication) , materials science , hexagonal phase , crystallography , chemistry , condensed matter physics , crystal structure , optics , physics , ferroelectricity , medicine , organic chemistry , endocrinology , optoelectronics , dielectric
Brillouin spectra of lithium potassium sulfate have been obtained in its hexagonal phase from room temperature to the orthorhombic phase transition temperature at 435°C. The ν 11 longitudinal sound velocity corresponding to the C 11 elastic coefficient undergoes a smooth decrease with increasing temperature; the maximum decrease is 6.0% at T 0 =435°C and the temperature dependence of ν 11 satisfies an expression of form\documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{{V_{11} (T)}}{{V_{11} (293\,{\rm K})}} = A - BT - \frac{C}{{T_c - T}} $$\end{document}with B =(1.13±0.04) × 10 −4 K −1 , C = (0.9±0.1) K and T c = (467±6)°C=(740±6)K.