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 BaFe 2− x Ru x As 2 ( x ≈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 ( μ 0 H =0.1 T) is well described through a glassy exponent μ =1.9 and a collective pinning energy ( U 0 ) smaller than 100 K.