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

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${}_7$.

10 figures, 26 pages. Appeared in Physical Review B, vol-79, pp-134112 (2009)

References in corpus (5)

• Phonon and crystal field excitations in geometrically frustrated rare earth titanates
• Structural distortion and the spin liquid state in Tb2Ti2O7
• Structural Fluctuations in the Spin Liquid State of Tb2Ti2O7
• Manifestation of geometric frustration on magnetic and thermodynamic properties of pyrochlores $S{m}_2{X}_2{O}_7$ (X=Ti, Zr)
• Temperature dependent Raman and x-ray studies of spin-ice pyrochlore $D{y}_{2}T{i}_2{O}_7$ and non-magnetic pyrochlore $L{u}_{2}T{i}_2{O}_7$

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