The influence of the buffer layer architecture on transport properties for BaFe1.8Co0.2As2 films on technical substrates

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 IBAD-MgO/Y$_2$O$_3$ 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.