Surface properties of Co-doped BaFe2As2 thin films deposited on MgO with Fe buffer layer and CaF2 substrates

Surface properties of Co-doped BaFe2As2 (Ba-122) thin films prepared by pulsed laser deposition on MgO with Fe buffer layer and CaF2 substrates were inspected by atomic force microscopy, scanning spreading resistance microscopy, scanning tunneling microscopy, X-ray photoelectron spectroscopy, auger electron spectroscopy/microscopy and point contact spectroscopy (PCS). Selected PCS spectra were fitted by extended 1D BTK model. The measurements were done on as-received as well as ion beam etched surfaces. Our results show that the substrate is considerably influencing the surface properties of the films, particularly the topography and surface conductivity distribution, what can affect results obtained by surface-sensitive techniques like PCS.