Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 16: CE: Quantum-Critical Phenomena 1
TT 16.8: Vortrag
Dienstag, 23. März 2010, 15:45–16:00, H19
Low temperature properties of single crystal Fe2TiSn under high pressure and magnetic field — •Andreas Neubauer1, Michael Schulz1,2, Christian Pfleiderer1, Peter Böni1, Klaudia Hradil2, and Günther Behr3 — 1Physik Department E21, Technische Universität München, 85748 Garching, Germany — 2Technische Universität München, Forschungsneutronenquelle Heinz Maier Leibnitz (FRM II),Lichtenbergstr. 1, 85748 Garching, Germany — 3Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, PF270116, 01171 Dresden, Germany
Electronic structure calculations predict a paramagnetic ground state for the Heusler compound Fe2TiSn. However, the experimental investigation of polycrystals showed weakly ferromagnetic behaviour (TC∼250 K), where the magnetic properties are extremely sensitive to sample synthesis. We were able to grow, for the first time, single crystals of Fe2TiSn by the optical float zoning using an UHV-compatible image furnace. The inverse AC susceptibility of the single crystals shows a paramagnetic Curie-Weiss-behaviour from room temperature down to around 5K, followed by a transition to a so far unidentified phase. Interestingly, the inverse susceptibility extrapolates through T=0, a behaviour expected for ferromagnetic quantum criticality. We investigated the pressure dependence of the magnetization, the longitudinal magneto-resistance and the Hall effect. These data are supplemented by neutron depolarization measurements. Possible implications of our observations for the possible nature of quantum criticality in Fe2TiSn will be discussed.