Magnetic granularity in PLD-grown Fe(Se,Te) films on simple RABiTS templates

Abstract

Iron-based superconductors are a popular candidate in the search for affordable and simple superconductors for high-field applications. In particular, the relaxed texture requirements fuel hope that films deposited on RABiTS with simple buffer layer architectures could enable cheap coated conductors. We find that a single Yttrium oxide buffer layer can act as a suitable diffusion barrier and epitaxial Fe(Se,Te) thin films were successfully grown by pulsed laser deposition. An analysis of the local current distribution by means of scanning Hall probe microscopy reveals current densities exceeding 1 MA cm-2, however, granularity still seems to be an issue. Transmission electron microscopy images and analysis by transmission Kikuchi diffraction show that the out-of-plane orientation of underlying Ni-W grains in the substrate has a severe impact on the growth of Fe(Se,Te) films.