Vibrational spectroscopic studies of the ferroelectric LiRbSO4

Chary, BR and Bhat, HL and Chandrasekhar, P and Narayanan, PS (1986) Vibrational spectroscopic studies of the ferroelectric LiRbSO4. In: Journal of Raman Spectroscopy, 17 (1). pp. 59-63.

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Abstract

Lithium rubidium sulphate, LiRbSO4 (LRS), undergoes a sequence of four phase transitions at 166, 185, 202 and 204°C. The phase between 202 and 204°C is incommensurate. Polarized phonon Raman spectra in the frequency region of 50-1200 cm-1 are presented to identify the external and internal vibrational modes at room temperature. The internal mode frequencies of the sulphate ions are presented in the temperature region from -150 to 230°C covering all the phase transitions. The total integrated areas of the 1, 2 and 4 modes show an anomalous increase across the phase transitions. The frequencies of the symmetric stretching (1) and symmetric bending (2) modes do not show any changes at the phase transitions, but the width of the 2 mode shows changes across the phase transitions. A small increase in the linewidth of the 2 mode observed in the incommensurate phase is attributed to the influence of the incommensurate modulation wave. A DSC thermogram showed endothermic peaks during heating at all the phase transitions. The IR spectrum recorded at room temperature showed the expected Au and Bu internal modes.

Item Type:	Journal Article
Publication:	Journal of Raman Spectroscopy
Publisher:	John Wiley and Sons
Additional Information:	Copyright of this article belongs to John Wiley and Sons.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	27 Jan 2010 09:51
Last Modified:	28 Feb 2019 08:52
URI:	http://eprints.iisc.ac.in/id/eprint/22697

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