The influence of the buffer layer architecture on transport properties for BaFe_(1.8)Co_(0.2)As_2 films on technical substrates

摘要

A low and almost temperature independent resistance in the normal state and an anomalous peak effect within the normal-superconducting transition have been observed in BaFe_(1.8)Co_(0.2)As_2/Fe bilayers, prepared on ion beam assisted deposition-MgO/Y_2O_3 buffered technical substrates. A resistor network array sufficiently reproduces this effect, assuming an increase of the electrical conductance between tape and film with decreasing buffer layer thickness. Based on this model, we evaluated the influence of this effect on the critical current density and successfully reconstructed the superconducting transition of the bilayer.