The electrical resistivity (Rxx) and Hall resistivity (Rxy) of LaFeAsO1-xFx have been measured over a wide fluorine doping range 0 =< x =< 0.14 using 60 T pulsed magnets. While the superconducting phase diagram (Tc, x) displays the classic dome-shaped structure, we find that the resistive upper critical field (Hc2) increases monotonically with decreasing fluorine concentration, with the largest Hc2 >= 75 T for x = 0.05. This is reminiscent of the composition dependence in high-Tc cuprates and might correlate with opening of a pseudo-gap in the underdoped region. Further, the temperature dependence of Hc2(T) for superconducting samples can be understood in terms of multi-band superconductivity. Rxy data for non-superconducting samples show non-linear field dependence, which is also consistent with a multi-carrier scenario.
@article{arxiv.0809.1133,
title = {Doping dependence of upper critical field and Hall resistivity in LaFeAsO1-xFx},
author = {Y. Kohama and Y. Kamihara and S. A. Baily and L. Civale and S. C. Riggs and F. F. Balakirev and T. Atake and M. Jaime and M. Hirano and H. Hosono},
journal= {arXiv preprint arXiv:0809.1133},
year = {2015}
}