Effect of the Buffer Layers on the Performance of Fe(Se, Te) Films Fabricated on IBAD Metal Templates by Pulsed Laser Deposition

In the development of Fe(Se, Te) films, the substrate is thought to be a consequential factor in the growth and characteristics of the films. In this study, Fe(Se, Te) films were grown on ion beam-assisted deposition flexible metallic templates with MgO, CeO 2 , LaMnO 3 , and SrTiO 3 as buffer layers by pulsed laser deposition to explore the influence of buffer layers. The surface morphology, crystalline structure, chemical component, and superconductivity of the films were investigated. All the films have a smooth surface and a highly biaxial texture structure and present point and surface pinning centers with the dominance of surface pinning. Although the lattice constant of Fe(Se, Te) film is not significantly related to the lattice mismatch between the buffer layer and the Fe(Se, Te) film, the crystallinity and the critical current density J c of the film are negatively correlated with the lattice mismatch. The critical temperature T c declines as a -axis length increases. In-plane compressive strain and crystallinity are the main variables impacting superconductivity. In addition, the Fe(Se, Te) film grown on CeO 2 had the best superconducting properties with T_c^0 =16.4 K and T_c^onset =16.8 K. The self-field J c was 2.26 MA/cm 2 at 4.2 K and can maintain 10 5 A/cm 2 at 9 T. The upper critical field can reach 53 T allowing the applications of Fe(Se, Te) coated conductors in high field.