Structural and superconducting properties of (Y,Gd)Ba₂Cu ₃O_7-δ grown by MOCVD on samarium zirconate buffered IBAD-MgO

Textured samarium zirconate (SZO) films have been grown by reactive cosputtering directly on an ion beam assisted deposited (IBAD) MgO template, without an intermediate homoepitaxial MgO layer. The subsequent growth of 0.9 μm thick (Y,Gd)Ba₂Cu₃O_7-δ ((Y, Gd)BCO) films by metal organic chemical vapor deposition (MOCVD) yielded well textured films with a full width at half maximum of 1.9° and 3.4° for the out-of-plane and in-plane texture, respectively. Microstructural characterizations of the SZO buffered samples revealed clean interfaces. This indicates that the SZO not only provides a diffusion barrier, but also functions as a buffer for (Y, Gd)BCO grown by MOCVD. The achievement of self-field critical current densities (J_c) of over 2 MA cm^-2 at 75.5 K is another proof of the effectiveness of SZO as a buffer on the IBAD-MgO template. The in-field measurements revealed an asymmetric angular dependence of J_c and a shift of the ab-plane maxima due to the tilted nature of the template and (Y,Gd)₂O₃ particles existing in the (Y, Gd)BCO matrix. The present results are especially important because they demonstrate that high temperature superconducting coated conductors with simpler architecture can be fabricated using commercially viable processes.