Fluorine Doping Effect On Hc2 and Rh In LaFeAsO1-xFx
Abstract
The iron arsenide superconductors discovered earlier this year have attracted much interest, and some families showing high-Tc have been identified. LnFeAsO (Ln; lanthanide) is the first copper-free family of compounds with Tc exceeding 50 K. Here, we present the first systematic study of Hc2 and RH in the wide fluorine doping region (LaFeAsO1-xFx; x = 0, 0.25, 0.05, 0.07, 0.11 and 0.14). We found that Hc2 increases monotonically with decreasing x, while the superconducting phase diagram (Tc, x) displays the classic dome-shaped structure. Furthermore, the shape of Hc2(T) depends strongly on x. This, according to Gurevich's model, suggests a multiband electronic structure. The Hall resistivity for non-superconducting samples x = 0, 0.025 show a non-linear magnetic field dependence, which also supports a multiband electronic structure interpretation. In addition, the estimated low-field limit of the RH for x = 0, 0.025 detect a gap opening at the structural transition and magnetic transition. The evidence for multiband electronic structure links these materials to famous multiband superconductor MgB2 rather than high-Tc cuprates.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2009
- Bibcode:
- 2009APS..MARY35001K