The magnetoresistance of a PrFeAsO_1−<i>x</i>F_<i>y</i>superconductor

Abstract

We have measured the temperature and magnetic field dependence of resistivity of polycrystalline PrFeAsO0.60F0.12 samples in the normal and superconducting state. The superconducting onset transition temperature Tcon shifts by ∼4 K as H is increased from 0 to 14 T. The zero-temperature upper critical field Hc2(0) estimated by using the Ginzburg–Landau theory and the Werthamer–Helfand–Hohenberg equation exceeds 100 T. The resistivity below Tcon exhibits Arrhenius behavior due to thermally activated flux flow of vortices. The activation energy U0, determined from the Arrhenius plot of the resistivity, shows a power-law decrease () with magnetic field. The normal-state magnetoresistance varies quasilinearly with magnetic field and does not obey Kohler's rule, suggesting a multiband feature of the material.