Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 78: Correlated Electrons: Poster Session
TT 78.19: Poster
Donnerstag, 10. März 2016, 15:00–18:30, Poster D
Investigation of the Thermodynamic Properties of Insulating Pyrochlores — •J. Gronemann1,2, E. L. Green1, R. Schönemann1,2, M. Uhlarz1, H.D. Zhou3, M. Ruminy4, T. Fennell4, M. Kenzelmann4, and J. Wosnitza1,2 — 1HLD-EMFL, HZDR, Dresden, Germany — 2TU Dresden, Germany — 3Univ. of Tennessee, Knoxville, USA — 4PSI, Villingen, Switzerland
Geometrically frustrated pyrochlores have gained interest in recent years due to their novel low temperature properties. In the insulating compounds Pr2Sn2O7 and Tb2Ti2O7 the magnetic Pr3+ and Tb3+ ions form corner sharing tetrahedrons and can develop long or short-range order corresponding to a spin-ice or spin-liquid state, respectively. Heat capacity was measured down to 100 mK to investigate the low temperature ground state. Despite the similarities between both samples (similar crystal structures and a non-Kramers doublet in the ground state [1-2]) our measurements show no long-range magnetic order in Tb2Ti2O7 down to 100 mK, a possible spin-liquid candidate, while in contrast Pr2Sn2O7 is a well-known “dynamic” spin-ice compound as evidenced by a sharp specific heat anomaly around 800 mK [2] and confirmed by our recent AC susceptibility measurements. Though in typical spin-ice compounds the anomaly is suppressed by applying high magnetic fields, in Pr2Sn2O7, however, the peak broadens and shifts to higher temperatures with increasing field. Further investigations are underway to determine the exact nature of this state and why it differs so drastically from the isostructural Tb2Ti2O7.
L. Ventelon et al., PRB 91, 224430 (2015)
H. D. Zhou et al., PRL 101, 227204 (2008)