An evaluation of phase separated, self-assembled LaMn0₃-MgO nanocomposite films directly on IBAD-MgO as buffer layers for flux pinning enhancements In YBa₃Cu₃O_7-δ. coated conductors

Technological applications of iiigii temperature superconductors (HTS) require iiigii critical current density, ic, under operation at high magnetic field strengths. This requires effective flux pinning by introducing artificial defects through creative processing. In this work, we evaluated the feasibility of mixed-phase LaMnO₃:MgO (LMO:MgO) films as a potential cap bufferlayer for the epitaxial growth and enhanced performance of YBa ₂Cu₃0₇-δ (YBCO) films. Such composite films were sputter deposited directly on IBAD-MgO templates (with no additional homo-epitaxial MgO layer) and revealed the formation of two phase-separated, but at the same time vertically aligned, self-assembled composite nanostructures that extend throughout the entire thickness of the film. The YBCO coatings deposited on these nanostructured cap layers showed correlated c-axis pinning and improved in-field J_c performance compared to those of YBCO films fabricated on standard LMO buffers. Microstructural characterization revealed additional extended disorder in the YBCO matrix. The present results demonstrate the feasibilityof novel and potentially practical approaches in the pursuit of more efficient, economical, and high performance superconducting devices.