Berlin 2008 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 32: Correlated Electrons: Poster Session

TT 32.13: Poster

Donnerstag, 28. Februar 2008, 14:00–18:00, Poster B

Magnetic excitations in CeCu₂Ge₂ — •Astrid Schneidewind¹, Oliver Stockert², Karin Schmalzl³, Micha Deppe², Julia Arndt², Christoph Geibel², Frank Steglich², and Michael Loewenhaupt¹ — ¹Inst. f. Festkörperphysik, TU Dresden, D-01062 Dresden, Germany — ²Max-Planck-Institut-CPfS, D-01178 Dresden, Germany — ³Jülich Centre of Neutron Science, D-52425 Jülich, Germany, and Institut Laue-Langevin, F-38042 Grenoble, France

CeCu₂Ge₂ is a heavy-fermion compound showing incommensurate antiferromagnetic order with Kondo-compensated moments below T_N = 4.15 K [1,2]. Calculations of the Fermi surface show that a local character of the Ce 4f moments is not able to explain the incommensurate nesting vector as observed [3]. Involving an also itinerant component of the Ce 4f moments results in a nesting vector q which agrees well with the experimental values of q [3]. Since magnetic excitations are sensitive on the localization of the magnetic moments, we started to study the magnetic excitation spectrum to understand the magnetic order in CeCu₂Ge₂. In a first neutron scattering experiment on a CeCu₂Ge₂ single crystal the magnetic propagation vector was confirmed to be incommensurate and temperature dependent as reported by Krimmel et al. [2]. Furthermore, magnetic excitations have clearly been detected at low energies (ℏω ≤ 2 meV) below T_N displaying different temperature and q-dependences.