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

TL;DR

This study investigates how buffer layer architecture affects the transport properties of BaFe1.8Co0.2As2 films on technical substrates, revealing the impact on resistance behavior and critical current density through experimental and modeling approaches.

Contribution

It introduces a resistor network model to explain the influence of buffer layer thickness on electrical conductance and superconducting transition in BaFe1.8Co0.2As2 bilayers.

Findings

Resistivity remains low and nearly temperature independent in the normal state.

An anomalous peak effect occurs within the normal-superconducting transition.

The buffer layer thickness significantly influences the electrical conductance and critical current density.

Abstract

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.