Identification of a self-limiting reaction layer in Ni-3 at.% W rolling-assisted biaxially textured substrates

Analytical transmission electron microscopy was used to identify the presence of a self-limiting reaction layer developed within rolling-assisted biaxially textured Ni-3 at.% W substrates during the pulsed laser deposition of thick YBa₂Cu₃O_7-δ (YBCO) films. Improvements in YBCO film quality and physical properties were attributed in part to the development of a NiWO₄ layer at the buffer-substrate interface. The formation of NiWO₄ between NiO and the Ni-3 at.% W substrate was observed to restrict the growth of NiO within the coated conductor during YBCO deposition at elevated temperatures. A 5-8 nm thick NiWO ₄ layer, identified through both electron diffraction and energy dispersive spectroscopy, was found to limit NiO growth to between 20 and 25 nm in thickness. The NiWO₄ layer was found to have a [100] orientation relationship to the substrate normal, with multiple variants observed.