You are here

    • You are here:
    • Home > ST146 - Upper Critical Fields up to 60 T and the Vortex Matter Phase Diagram of Arsenic-deficient LaO0.9F0.1FeAs1-δ

ST146 - Upper Critical Fields up to 60 T and the Vortex Matter Phase Diagram of Arsenic-deficient LaO0.9F0.1FeAs1-δ

Upper Critical Fields up to 60 T and the Vortex Matter Phase Diagram of Arsenic-deficient LaO0.9F0.1FeAs1-δ

G. Fuchs1, S.-L. Drechsler1, N. Kozlova1, V. Grinenko1, J. Freudenberger1,
M. Bartkowiak2, G. Behr1, C. Hess1, R. Klingeler1, A. Köhler1,
K. Nenkov1, H.-H. Klauss3, B. Büchner1 and L. Schultz1

1IFW Dresden, Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden,
P.O. Box 270116, D-01171 Dresden, Germany
2Hochfeld-Magnetlabor Dresden, FZ Dresden-Rossendorf (FZD), Germany
3Institut für Festkörperphysik, TU Dresden, Germany

E-mail: [email protected]

ABSTRACT - We report resistivity, magnetization and upper critical field Bc2(T) data for arsenic deficient LaO0.9F0.1FeAs1-δ in a wide temperature and high field range up to 60 T. These disordered samples exhibit a slightly enhanced transition temperature of Tc = 29.0 K and a significantly enlarged slope dBc2/dT = –5.4 T/K near Tc. The
high-field Bc2(T) data obtained from resistance measurements in pulsed magnetic fields follow up to about 30 T the WHH (Werthamer-Helfand-Hohenberg) curve for the orbital limited upper critical field, but show a clear flattening above 30 T. This flattening evidences Pauli limiting behavior (PLB) with Bc2(0)≈63 T. We compare our results with Bc2(T) data reported in the literature for clean and disordered samples. Whereas clean samples show no PLB for fields below 70 T as measured so far, the hitherto unexplained flattening of Bc2(T) for applied fields H||ab observed for several disordered closely related systems is interpreted as a manifestation of PLB. The influence of the arsenic vacancies in LaO0.9F0.1FeAs1-δ on the vortex matter phase diagram is studied by magnetization measurements on bulk samples
.

IEEE/CSC & ESAS EUROPEAN SUPERCONDUCTIVITY NEWS FORUM (ESNF), No. 11, January 2010
Published in Journal of Physics Conf. Series (SuST234, 012013 (2010)