Dresden 2006 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

TT: Tiefe Temperaturen

TT 3: Correlated Electrons: Quantum-Critical Phenomena

TT 3.3: Vortrag

Montag, 27. März 2006, 10:00–10:15, HSZ 301

Metamagnetic quantum criticality in Sr₃Ru₂O₇ studied by thermal expansion — •P. Gegenwart¹, F. Weickert¹, M. Garst², R.S. Perry^3,4,5, and Y. Maeno^4,5 — ¹Max-Planck Institute for Chemical Physics of Solids, Dresden, Germany — ²Theoretical Physics Institute, University of Minnesota, USA — ³School of Physics and Astronomy, University of St. Andrews, Fife KY16 9SS, Scotland — ⁴International Innovation Center, Kyoto University, Japan — ⁵Department of Physics, Kyoto University, Japan

We report low-temperature thermal expansion measurements on the bilayer ruthenate Sr₃Ru₂O₇ as a function of magnetic field applied perpendicular to the Ruthenium-oxide planes. The field-dependence of the c-axis expansion coefficient indicates the accumulation of entropy close to 8 Tesla, related to an underlying quantum critical point. The latter is masked by two first-order metamagnetic transitions which bound a regime of enhanced entropy. Outside this region the singular thermal expansion behavior is compatible with the predictions for a two-dimensional metamagnetic quantum critical end point (work available at cond-mat/0507359).

Helpful discussions with S.A. Grigera, A.P. Mackenzie, A. Rosch and P. Wölfle are gratefully acknowledged. P.G. thanks the Deutsche Forschungsgemeinschaft (DFG grant GE 1640/1-1) and Royal Society (UK) for support of his stay at the St. Andrews University, M.G. is supported by DFG grant GA 1072/1-1.