Temperature-dependent Raman Study of the Pyrochlore Spin Liquid Compound Tb2Ti2O7
M. Maczka; M.L. Sanjuán; A.F. Fuentes; K. Hermanowicz; J. Hanuza.. Temperature-dependent Raman Study of the Pyrochlore Spin Liquid Compound Tb2Ti2O7 . Physical Review B (ISSN: 1098-0121) . 2008, Vol. 78, p. 134420-1-2008.
Temperature-dependent Raman scattering studies of the Tb2Ti2O7 geometrically frustrated pyrochlore are presented. The Raman spectra have shown softening of the majority of phonon modes upon cooling in the whole temperature range studied and a large decrease of linewidths. These changes have been analyzed in terms of phonon-phonon anharmonic interactions. A departure from the expected behavior has been observed at low temperatures for the A1g mode, which is attributed to the spin-phonon coupling. The Raman studies have also revealed an unusual temperature dependence of the modes observed in the 290-350 cm-1 range. This behavior has been attributed to a very strong coupling between the crystal field excitations of the Tb3+ 4f electrons and the F2g phonon mode, which is a distinct feature of Tb2Ti2O7 spin liquid material among the family of rare earth titanates. Our studies have also shown several uncoupled crystal field excitations, which has provided for the first time information on energy levels of the 7F5 manifold
Temperature-dependent Raman scattering studies of the Tb2Ti2O7 geometrically frustrated pyrochlore are presented. The Raman spectra have shown softening of the majority of phonon modes upon cooling in the whole temperature range studied and a large decrease of linewidths. These changes have been analyzed in terms of phonon-phonon anharmonic interactions. A departure from the expected behavior has been observed at low temperatures for the A1g mode, which is attributed to the spin-phonon coupling. The Raman studies have also revealed an unusual temperature dependence of the modes observed in the 290-350 cm-1 range. This behavior has been attributed to a very strong coupling between the crystal field excitations of the Tb3+ 4f electrons and the F2g phonon mode, which is a distinct feature of Tb2Ti2O7 spin liquid material among the family of rare earth titanates. Our studies have also shown several uncoupled crystal field excitations, which has provided for the first time information on energy levels of the 7F5 manifold