Direct observation of the depairing current density in single-crystalline Ba0.5K0.5Fe2As2 microbridge with nanoscale thickness

We investigated the critical current density (J(c)) of Ba0.5K0.5Fe2As2 single-crystalline microbridges with thicknesses ranging from 276 to 18 nm. The J(c) of the microbridge with thickness down to 91 nm is 10.8 MA/cm(2) at 35 K, and reaches 944.4 MA/cm(2) by extrapolating J(c)(T)to T = 0K using a two-gap s-wave Ginzburg-Landau model, well in accordance with the depairing current limit. The temperature, magnetic field, and angular-dependence of J(c)(T, H, theta)indicated weaker field dependence and weakly anisotropic factor of 1.15 (1 T) and 1.26 (5 T), which also yielded the validity of the anisotropic Ginzburg-Landau scaling. (C) 2013 AIP Publishing LLC.