Regensburg 2002 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 7: Postersitzung I: Anwendungen der Supraleitung (1-6), Dünne Schichten, Josephsonkontakte, SQUIDs (7-17), Neue und unkonv. Supraleiter(18-23), Amorphe- und Tunnelsyst. (24-28), Quantenflüssigkeiten (29-30), Syst. korr. Elektr.: Theorie I (31-45)
TT 7.21: Poster
Montag, 11. März 2002, 14:30–18:00, A
Low temperature specific heat of polycrystalline UGe 2 at high pressure — •Ralf Vollmer1, Christian Pfleiderer1, Hilbert v. Löhneysen1,2, Eric D. Bauer3, and M. Brian Maple3 — 1Physikalisches Institut, Universität Karlsruhe, D-76128 Karlsruhe — 2Forschungszentrum Karlsruhe, Institut für Festkörperphysik, D-76021 Karlsruhe, Germany — 3Institute for Pure and Applied Physical Sciences and Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
In UGe 2 , superconductivity in coexistence with ferromagnetism is observed in single crystal [1] and polycrystalline samples [2] the pressure pc≈ 16 kbar for which the Curie temperature TC drops to zero. We present measurements of the specific heat C in the range 0.1 K to 2.5 K on polycrystalline samples up to 14.7 kbar. The linear coefficient of the specific heat, γ =C/T , increases as a function of pressure and is the highest in the p -range where superconductivity is observed. In the superconducting state the a.c. magnetic susceptibility exhibits strong diamagnetic shielding. The specific heat displays an anomaly that is indicative of a bulk superconducting transition of order 15 to 20% by volume. The observed properties reflect an intricate interplay of the coexistence of ferromagnetism and superconductivity in UGe 2 .
[1] S. Saxena et al., Nature 406 (2000) 587; A. Huxley et al., Phys. Rev. B 63 (2001) 144519.
[2] E. D. Bauer et al., J. Phys.: Cond. Matt. 13 (2001) L759.