Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 26: CE: Heavy Fermions
TT 26.10: Vortrag
Mittwoch, 24. März 2010, 16:30–16:45, H21
Evidence for unconventional d-wave superconducting state in CeCu2Si2 — •Hugo A. Vieyra1, David Parker2, Hirale S. Jeevan3, Christoph Geibel1, Frank Steglich1, and Niels Oeschler1 — 1Max Planck Institute for Chemical Physics of Solids. Dresden 01187, Germany — 2US Naval Research Laboratory. Washington, DC 20375, USA — 3I. Physik. Institut, Georg-August-Universität Göttingen, Göttingen 37077, Germany
The heavy-fermion CeCu2Si2 represents a prime system to study unconventional superconductivity in the vicinity of a magnetic instability. Within the homogeneity range of pure CeCu2Si2 different ground states can be obtained. S-type crystals exhibit a superconducting transition at Tc=0.6 K, whereas A/S-type show in addition antiferromagnetic order at TN=0.8 K. In recent years, the synthesis techniques have been optimized in order to obtain large high-quality single crystals with well defined ground state properties. This allows the systematic study of the superconducting order parameter and its variation at the border with magnetic order. In this work, we present angular dependent resistivity measurements on high-quality S- and A/S-type single-crystalline CeCu2Si2 samples. The experimental results for the angular dependence of the upper critical field Bc2 as well as theoretical calculations taking into account effects like the strong Pauli paramagnetism, hint towards an unconventional d-wave symmetry of the order parameter in CeCu2Si2.