Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 39: Correlated Electrons: Heavy Fermions 1
TT 39.7: Vortrag
Donnerstag, 26. März 2009, 11:30–11:45, HSZ 304
Superconductivity in CeCu2Si2: evidence of fermisurface change — •Enrico Faulhaber1, Oliver Stockert2, Wolfgang Schmidt3,4, Karin Schmalzl3,4, Christoph Geibel2, Frank Steglich2, and Michael Loewenhaupt1 — 1TU Dresden; Institut für Festkörperphysik; D-01062 Dresden — 2Max-Planck-Institut für Chemische Physik fester Stoffe; D-01187 Dresden — 3Forschungszentrum Jülich GmbH; Institut für Festkörperforschung; D-52425 Jülich — 4Institut Laue-Langevin; F-38042 Grenoble
The first discovered heavy fermion superconductor CeCu2Si2 has been investigated for nearly 30 years now. Key properties of the material are an antiferromagnetic order below 1 K dominated by a nesting of the Fermi surface and a superconducting phase below ≈0.6 K. This phase seems to depend on the magnetism in the material, possibly pointing towards a magnetically mediated superconductivity.
In a recent experiment we investigated the delicate relationship between the magnetic and superconducting phases. We used the neutron scattering technique to observe the magnetic propagation vector. Also, the instrument was complemented with a unique in-situ ac-susceptibility setup to record the superconductivity of the sample during the neutron diffraction. Applying a magnetic field, we found an unexpected change of the magnetic propagation vector which correlates well with the superconducting volume. This shift is absent in non-superconducting samples, indicating a strong entanglement of both phenomena (superconductivity and magnetism) and might point to a change of the Fermi surface caused by the superconductivity.