The role of thermally and chemically stable composite Y₂O ₃:Al₂O₃ in the development of YBa ₂Cu₃O_7-x films on metal substrates

We have developed Y₂O₃:Al₂O₃ (YAlO) composites to simplify the architecture of superconducting YBa ₂Cu₃O_7-x (YBCO) thick films on polycrystalline metal substrates. By implementing the use of YAlO, we have reduced the total number of non-superconducting layers between the polycrystalline metal substrate and the YBCO film from five (as in the standard architecture used by industry) to three. The YBCO films grown on this simplified platform exhibited an in-plane mosaic spread of less than 4° in full width at half-maximum, correlated pinning centered at , and an α value (the proportionality factor of the critical current density H^-α) of around 0.38 over the field range of 0.1-1.0T. We believe that the excellent structural stability at high temperatures and the exceptional chemical inertness in an oxidizing environment make YAlO a good choice for use in the growth of biaxially oriented MgO and subsequent buffer and superconducting layers.