Critical current densities and flux creep rates in near optimally doped BaFe2-xRuxAs2 (x=0.7) single crystals

Abstract

We present an investigation of the critical current densities J(c) and flux creep rates in a near optimally doped BaFe2-xRuxAs2 (x approximate to 0.7) single crystal by (measuring magnetization). The superconducting critical temperature is 18 K. The in-field dependences of the critical current density J(c) are due to a mixed pinning scenario produced mainly by large precipitates and a less significant contribution of random disorder. Furthermore, a Maley analysis in the regime dominated by strong pinning centers (mu H-0=0.1 T) is well described through a glassy exponent mu=1.9 and a collective pinning energy (U-0) smaller than 100 K.