Berlin 2008 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 15: Superconductivity: Poster Session
TT 15.19: Poster
Tuesday, February 26, 2008, 14:00–18:00, Poster B
Superconductivity on the Border of Weak Itinerant Ferromagnetism in UCoGe — N. T. Huy1, A. Gasparini1, D. E. de Nijs1, Y. Huang1, J. C. P. Klaasse1, T. Gortenmulder1, A. de Visser1, •A. Hamann2, T. Görlach2, and H. v. Löhneysen2,3 — 1Van der Waals-Zeeman Institute, University of Amsterdam, Valckenierstraat 65, 1018 XE Amsterdam, The Netherlands — 2Physikalisches Institut, Universität Karlsruhe, D-76128 Karlsruhe, Germany — 3Forschungszentrum Karlsruhe, Institut für Festkörperphysik, D-76021 Karlsruhe, Germany
We report the coexistence of ferromagnetic order and superconductivity in UCoGe at ambient pressure [1]. Magnetization measurements show that UCoGe is a weak ferromagnet with a Curie temperature TC ≈ 3 K and a small ordered moment m0 ≈ 0.03 µB. Superconductivity is observed with a resistive transition temperature Ts ≈ 0.8 K for the best sample. Thermal-expansion and specific-heat measurements provide solid evidence for bulk magnetism and superconductivity. The proximity to a ferromagnetic instability, the defect sensitivity of Ts, and the absence of Pauli limiting, suggest triplet superconductivity mediated by critical ferromagnetic fluctuations.
[1] N. T. Huy et al., PRL 99, 067006 (2007)