Titanium Nitride Epitaxial Film: Innovative Non-Oxide Buffer Layer for Fe(Se,Te) Coated Conductors

Coated conductors (CC) of iron-based superconductors (IBS) can compete with current technologies in high-field and low-temperature applications if a simplified tape design can be developed. We propose a CC architecture that utilizes a thin TiN single buffer layer on RABiTS substrates, combined with a Fe(Se,Te) bilayer. Fe(Se,Te) films with sharp texture and smooth morphology can be deposited on TiN-buffered Ni-W tape and serve as a seed layer. The Fe(Se,Te) top layer, deposited at a relatively low temperature, typically exhibits critical temperatures of about 17 K, and outstanding critical current densities around 0.1 MA/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 4.2 K in an applied magnetic field of 17.5 T. The proposed architecture ensures that the superconducting films are electrically connected to the metallic substrate, which can serve as an intrinsic stabilizer.