Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 35: Correlated Electrons - Quantum Critical Phenomena
TT 35.2: Vortrag
Mittwoch, 9. März 2005, 11:30–11:45, TU H104
Ferromagnetic Quantum Phase Transition of Single Crystalline CeSi1.81 under High Pressure — •Sandra Drotziger1, Christian Pfleiderer1,2, Marc Uhlarz1, Hilbert v. Löhneysen1,2, Dmitri Souptel3, Wolfgang Löser3, and Günter Behr3 — 1Physikalisches Institut, Universität Karlsruhe, D-76128 Karlsruhe, Germany — 2Forschungszentrum Karlsruhe, Institut für Festkörperphysik, D-76021 Karlsruhe, Germany — 3Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, PF 27 01 16, D-01171 Dresden, Germany
The rare-earth system CeSix develops ferromagnetic order at low temperatures for 1.50 < x < 1.85. With decreasing Si concentration a structural phase transition between a α -ThSi2 and a α -GdSi2 structure occurs. We report the pressure dependence of the magnetisation of single crystalline CeSi1.81 for magnetic fields parallel to the crystallographic a-axis, being an easy magnetic direction. Our samples belong to a new generation of CeSix single crystals, in which the structural phase transition is observed at x = 1.85. With increasing pressure the ordered magnetic moment µS and the Curie temperature TC disappear continuously above a critical pressure pc≈ 13±0.2 kbar. This behavior is consistent with the existence of a ferromagnetic quantum critical point at pc. In contrast to the existence of a quantum critical point, magnetic isotherms M(B) do not show clear evidence of a divergence of the uniform susceptibility at pc. The possible origin of these inconsistencies will be discussed.