Structural Fluctuations in the spin-liquid state of Tb2Ti2O7.
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.
Ruff
J P C
JP
Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1, Canada.
Gaulin
B D
BD
Castellan
J P
JP
Rule
K C
KC
Clancy
J P
JP
Rodriguez
J
J
Dabkowska
H A
HA