Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 20: Correlated Electrons - Poster Session

TT 20.14: Poster

Mittwoch, 28. März 2007, 14:00–17:45, Poster A

Magnetic-field-induced Change of the Fermi Surface in CeBiPt — •M Bartkowiak¹, B Bergk¹, Y Skourski¹, J Wosnitza¹, I Opahle², S Elgazzar², M Richter², H v Löhneysen^3,4, T Yoshino⁵, and T Takabatake⁵ — ¹Hochfeld-Magnetlabor Dresden (HLD) FZ Dresden-Rossendorf, 01328 Dresden — ²IFW Dresden,PO Box 270116, 01171 Dresden — ³Physikalisches Institut, Universität Karlsruhe — ⁴Institut für Festkörperphysik, FZ Karlsruhe — ⁵Department of Quantum Matter, ADSM, Hiroshima University

Comparative experiments between the two semimetals CeBiPt and LaBiPt reveal changes of the Fermi surface in CeBiPt with respect to temperature, applied magnetic, field and chemical composition. It must be concluded that the strong temperature dependence of the Shubnikov-de Haas (SdH) frequency as well as the change of carrier concentration above a sample dependent critical field are associated with the 4f electrons introduced by the Ce atoms. We present Hall and magnetoresistance measurements up to 70 T obtained at our new pulsed high magnetic field laboratory in Dresden. We observe the disappearance of the SdH signal and a change of the Hall coefficient above a sample-dependent threshold field. Rather than at 25 T, as reported previously, we measured a threshold field of ≈ 40 T demonstrating the strong dependence of the Fermi surface on stoichiometry.