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arXiv · 0904.3630

Low temperature and high pressure Raman and x-ray studies of pyrochlore Tb$_2$Ti$_2$O$_7$ : phonon anomalies and possible phase transition

Surajit Saha·D. V. S Muthu·Surjeet Singh·B. Dkhil·R. Suryanarayanan·G. Dhalenne·H. K. Poswal·S. Karmakar·Surinder M. Sharma·A. Revcolevschi·A. K. Sood
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Abstract

We have carried out temperature and pressure-dependent Raman and x-ray measurements on single crystals of Tb$_2$Ti$_2$O$_7$. 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 $\sim$ 9 GPa. We discuss possible implications of our results on the spin-liquid behaviour of Tb$_2$Ti$_2$O$_7$.

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Surajit Saha, D. V. S Muthu, Surjeet Singh, B. Dkhil, R. Suryanarayanan, G. Dhalenne, H. K. Poswal, S. Karmakar, Surinder M. Sharma, A. Revcolevschi, A. K. Sood. 2009-04-23. Low temperature and high pressure Raman and x-ray studies of pyrochlore Tb$_2$Ti$_2$O$_7$ : phonon anomalies and possible phase transition. https://doi.org/10.1103/physrevb.79.134112

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