Regensburg 2010 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 27: CE: Poster Session
TT 27.20: Poster
Mittwoch, 24. März 2010, 14:00–18:00, Poster D1
Equivalence of pressure and concentration tuning in CeCu6−xAux — •O. Stockert1, A. Hamann2, V. Fritsch2, A. Schneidewind3, and H. v. Löhneysen2 — 1Max-Planck-Institut CPfS, Dresden, Germany — 2Karlsruhe Institute of Technology, Karlsruhe, Germany — 3Joint Research Group Helmholtz-Zentrum Berlin - Technische Universität Dresden, FRM-II, Garching, Germany
In the prototypical heavy-fermion system CeCu6−xAux two different quantum critical scenarios are discussed: the conventional spin-density-wave (SDW) scenario introduced by Hertz, Millis and Moriya and the local scenario by Schröder, Coleman, Si. While concentration and pressure tuning the quantum phase transition (QPT) are described by the local critical scenario, magnetic field tuning the QPT results in the conventional SDW scenario. In order to study how far the analogy between Au substitution and hydrostatic pressure holds, we performed elastic neutron scattering experiments on single crystalline CeCu5.5Au0.5 and investigated the magnetic structure under hydrostatic pressure. At a pressure of p = 8 kbar the Néel temperature and the propagation vector of the magnetic structure attain almost the values of CeCu5.7Au0.3. This concentration-pressure analogy away from the QPT is highly remarkable, since the ambient-pressure magnetic structures of CeCu5.5Au0.5 and CeCu5.7Au0.3 are quite different. The change of the magnetic structure of CeCu5.5Au0.5 under pressure appears to be of first order and to be determined by slight changes in the nesting properties of the Fermi surface. We will discuss our findings in comparison to the different QPTs in the system CeCu6−xAux.