Fishtail Effect and the Upper Critical Field in a Superconducting Ca-10(Pt4As8)(Fe2-xPtxAs2)(5)

Abstract

A single crystal of a superconducting Ca10(Pt4 As8)(Fe2−xPtxAs2)5 (x = 0.01) was grown by the Bridgman method. The transition temperature was 32 K. The penetration field, Hp, was measured and the superconducting parameters, κ, λ, and ξ, were obtained from Hp. A fitting function was derived for the field dependence of the magnetization (M−H curve) including the fishtail effect and the secondary peak using a statistical method. The temperature dependence of the upper critical field, Hc2, was obtained from the fitting function and Hc2(0) was estimated to be 134 T. In addition, the SDW transition in the normal state is reported. © 2016 Springer Science+Business Media New York