Composite ${\rm Y}_{2}{\rm O}_{3}-{\rm Al}_{2}{\rm O}_{3}$ as Diffusion Barrier/Nucleation Layer for HTS Coated Conductors Based on IBAD MgO

A composite layer has been successfully implemented in high temperature superconducting (HTS) coated conductors (CCs) based on ion beam assisted deposition (IBAD) MgO technology. This layer serves a dual function: a nucleation layer for the growth of high quality biaxially aligned MgO and a diffusion barrier to inhibit interdiffusion between the Ni-alloy substrate and the superconductor. The composition of the composite Y2O3-Al2O3 influences the texture and superconducting properties of YBCO films grown on STO buffered MgO/Y2O3-Al2O3/Ni-alloy. Our experimental results demonstrate that the superconducting properties of YBCO grown on STO buffered MgO/Y2O3-Al2O3/Ni-alloy are comparable with those of YBCO on standard architecture. The use of a single composite Y2O3-Al2O3 layer instead of individual layers of Y2O3 and Al2O3 for the fabrication of HTS CCs based on IBAD MgO provides advantages such as simplified architecture and potentially reduced cost due to the reduced number of fabrication steps.