Nearly isotropic upper critical fields in a SrFe1.85Co0.15As2 single crystal

Abstract

We study temperature dependent upper critical field H-c2 of a SrFe1.85Co0.15As2 single crystal (T-c = 20.2 K) along ab-plane and c-axis through resistivity measurements up to 50 T. For the both crystalline directions, H-c2 becomes nearly isotropic at zero temperature limit, reaching similar to 48 T. The temperature dependence of the H-c2 curves is explained by interplay between orbital and Pauli limiting behaviors combined with the two band effects. (C) 2009 Elsevier B.V. All rights reserved.