Regensburg 2002 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 3: Schwere Fermionen, Kondo-Systeme I
TT 3.5: Vortrag
Montag, 11. März 2002, 10:30–10:45, H18
Low temperature specific heat of PrOs4Sb12 — •Ralf Vollmer1, Andreas Faisst1, Christian Pfleiderer1, Hilbert v. Löhneysen1,2, M. Brian Maple3, and Erik Bauer3 — 1Physikalisches Institut, Universität Karlsruhe, D-76128 Karlsruhe — 2Forschungszentrum Karlsruhe, Institut für Festkörperphysik, D-76021 Karlsruhe — 3Department of Physics, University of California San Diego, La Jolla, CA 92093-0319, USA
PrOs4Sb12 is a heavy-fermion system which becomes superconducting at Tc = 1.8 K. Here we report measurements of the specific heat on single crystals. The specific heat jump at Tc resides on a large Schottky-type anomaly [1]. In a magnetic field B > 2 T, the anomaly becomes increasingly suppressed. At 10 T a minimum value of C/T ≈ 0.55 J/molK2 at 2.8 K is found, compared to the zero-field maximum of 2.4 J/molK2. At lower T, a maximum develops for B > 4.5 T which sharpens considerably and shifts to higher T with increasing B, occuring at 1 K at 6.65 T, the largest field available in our dilution refrigerator. The temperature where these maxima are seen correspond to shoulders or maxima in the electrical resistivity [2]. Further work is necessary to unravel the origin of the zero-field and 6-T anomalies. Concerning the superconductivity transition, detailed measurements indicate a double-peak structure similar to that in UPt3, which is shifted to lower T in a magnetic field and persists up to ∼ 0.5 T.
[1] E. D. Bauer et al., submitted to Physical Review Letters
[2] E. D. Bauer, private communication