Biaxially textured YBa2Cu3Ox films (0.3μm-thick) were deposited onto monocrystalline LaAlO3 and buffered Hastelloy-C276 substrates. After annealing in 18O at 400C, secondary-ion mass spectrometry was used to determine the O diffusion profiles, and several cation-diffusion profiles in various layers of the conductors. It was noted that oxygenation in the YBa2Cu3Ox/LaAlO3 specimen was relatively slow, and that hours were required for full oxygenation of the YBa2Cu3Ox. The O diffusion was rapid in the coated conductor, and was dominated by diffusion along a–b planes. Full oxygenation of a 0.3μm-thick YBa2Cu3Ox layer was achieved in several minutes. Cation interdiffusion was limited in the YBa2Cu3Ox/LaAlO3 specimen, but was significant in the coated conductor. An SrTiO3 layer, between textured MgO and YBa2Cu3Ox, limited the diffusion of cations from the various substrate layers and into the superconductor.

Oxygen and Cation Diffusion in YBCO Coated Conductors. S.Tsukui, R.E.Koritala, M.Li, K.C.Goretta, M.Adachi, J.E.Baker, J.L.Routbort: Physica C, 392-396[2], 841-6