Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 78: Correlated Electrons: Poster Session
TT 78.20: Poster
Donnerstag, 10. März 2016, 15:00–18:30, Poster D
Spin-strain effects in the frustrated magnet Tb2Ti2O7 at low temperatures — •Y. Gritsenko1,2, S. Zherlitsyn1, J. Wosnitza1,2, M. Ruminy3, T. Fennell3, and M. Kenzelmann4 — 1HZDR/HLD, Dresden, Germany — 2TUD/IFP, Dresden, Germany — 3PSI/LNS, 5232 Villigen PSI, Switzerland — 4PSI/LDM, 5232 Villigen PSI, Switzerland
Geometrically frustrated magnets have attracted much attention, due to their tendency to build unconventional ground states with exotic excitations. Tb2Ti2O7 possesses a pyrochlore lattice as building block of the crystallographic structure, providing a basis for geometric frustration. This cubic material features Curie-Weiss temperature of ΘCW = −19 K, but no long-range magnetic order has been detected down to 50 mK indicating a large frustration. The existence of a spin-liquid state has been suggested for Tb2Ti2O7. Here, we present results of ultrasonic investigations of this material. The magnetic field was applied along the [110] direction at temperatures of 20, 150 and 300 mK. Clear anomalies were found for different acoustic modes. The temperature dependence of the sound velocity shows a softening at about 500 mK and step-like features at about 150 mK suggesting a low-temperature phase transformation. This investigation sheds new light on the role of lattice degrees of freedom and magneto-elastic interactions in this material.
This work has been partially supported by DFG through SFB 1143. We acknowledge the support of the HLD at HZDR, member of the European Magnetic Field Laboratory (EMFL).