Phase Transition in Single Crystal Cs₂Nb₄O₁₁

Authors

Jianjun Liu, University of Nebraska at Omaha
E. P. Kharitonova, Moscow State University
Chun-Gang Duan, University of Nebraska at OmahaFollow
Wai-Ning Mei, University of Nebraska at OmahaFollow
R. W. Smith, University of Nebraska at OmahaFollow
John R. Hardy, University of Nebraska-LincolnFollow

Date of this Version

2005

Comments

Published in THE JOURNAL OF CHEMICAL PHYSICS 122, 144503 (2005). Copyright © 2005 American Institute of Physics. Used by permission.

Abstract

We studied temperature dependence of complex capacitance, impedance, and polarized Raman spectra of single crystal Cs₂Nb₄O₁₁. First, we observed a sharp λ-shaped peak at 165 °C in the complex capacitance, then found drastic changes in the Raman spectra in the same temperature range. Utilizing the pseudosymmetry search of structure space group, we attributed the observed anomalies to a structural change from the room temperature orthorhombic Pnn2 to another orthorhombic Imm2. We also measured room temperature polarized Raman spectra in different symmetries of normal vibrations and assigned high wavenumber Raman bands to the internal vibrations of NbO₆ octahedra and NbO₄ tetrahedra.