Photo-Assisted MOCVD Fabrication of YBCO Thick Films and Buffer Layers on Flexible Metal Substrates for Wire Applications

Abstract

Photo-assisted MOCVD has been developed for application to high-rate, high quality YBa2Cu3O 7-δ thin film production. This technique is now being applied to the fabrication of thick film YBa2Cu3O 7-δ on flexible metal substrates for wires and tapes. The unique application of photo-irradiation as the sole source of energy for the MOCVD reaction has resulted in extremely rapid growth rates for YBCO films with accompanying high superconducting performance. Typical YBCO films of thickness >1 μ m exhibit J c ≥ 1 × 106 A/cm2 and T c > 90 K on single crystal oxide substrates. Such films have now been integrated to metal substrates such as single crystal Ni(100) and roll-textured nickel foil. YBCO films grown on textured Ni foils with CeO2 and YSZ buffer layers show J c ≈ 3 to 5 × 105 A/cm2 for films of 1 μ m thickness grown in 2 to 4 minutes time. Such performance for thick films made in such short growth time is promising for YBCO wire fabrication. The development of effective YBCO wire through thick film growth on flexible substrates also requires buffer layer application. Photo-assisted MOCVD has also been applied to buffer layer formation with promising results.