Low-temperature and high-pressure Raman and x-ray studies of pyrochlore Tb2Ti2O7: Phonon anomalies and possible phase transition

Saha, Surajit and Muthu, DVS and Singh, Surjeet and Dkhil, B and Suryanarayanan, R and Dhalenne, G and Poswal, HK and Karmakar, S and Sharma, Surinder M and Revcolevschi, A and Sood, AK (2009) Low-temperature and high-pressure Raman and x-ray studies of pyrochlore Tb2Ti2O7: Phonon anomalies and possible phase transition. In: Physical Review B: Condensed Matter and Materials Physics, 79 (13).

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Abstract

We have carried out temperature- and pressure-dependent Raman and x-ray measurements on single crystals of Tb2Ti2O7. We attribute the observed anomalous temperature dependence of phonons to phonon-phonon anharmonic interactions. The quasiharmonic and anharmonic contributions to the temperature-dependent changes in phonon frequencies are estimated quantitatively using mode Grüneisen parameters derived from pressure-dependent Raman experiments and bulk modulus from high-pressure x-ray measurements. Further, our Raman and x-ray data suggest a subtle structural deformation of the pyrochlore lattice at ~9 GPa. We discuss possible implications of our results on the spin-liquid behavior of Tb2Ti2O7.

Item Type:	Journal Article
Publication:	Physical Review B: Condensed Matter and Materials Physics
Publisher:	The American Physical Society
Additional Information:	Copyright of this article belongs to The American Physical Society.
Keywords:	anharmonic lattice modes;deformation;elastic moduli;Gruneisen coefficient;high-pressure effects;phonon-phonon interactions;Raman. spectra; terbium compounds
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	09 Dec 2009 10:03
Last Modified:	19 Sep 2010 05:33
URI:	http://eprints.iisc.ac.in/id/eprint/20541

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