title: Structural Fluctuations in the spin-liquid state of Tb2Ti2O7.
abstract: High-resolution x-ray scattering measurements on single crystal Tb2Ti2O7 reveal finite structural correlations at low temperatures. This geometrically frustrated pyrochlore is known to exhibit a spin-liquid or cooperative paramagnetic state at temperatures below approximately 20 K. Parametric studies of structural Bragg peaks appropriate to the Fd3[over ]m space group of Tb2Ti2O7 reveal substantial broadening and peak intensity reduction in the temperature regime 20 K to 300 mK. We also observe a small, anomalous lattice expansion on cooling below a density maximum at approximately 18 K. These measurements are consistent with the development of fluctuations above a cooperative Jahn-Teller, cubic-tetragonal phase transition at very low temperatures.
authors.affiliation: Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1, Canada.
authors.forename: J P C
authors.initials: JP
authors.lastname: Ruff
authors.forename: B D
authors.initials: BD
authors.lastname: Gaulin
authors.forename: J P
authors.initials: JP
authors.lastname: Castellan
authors.forename: K C
authors.initials: KC
authors.lastname: Rule
authors.forename: J P
authors.initials: JP
authors.lastname: Clancy
authors.forename: J
authors.initials: J
authors.lastname: Rodriguez
authors.forename: H A
authors.initials: HA
authors.lastname: Dabkowska