High-resolution transmission electron microscopy/analytical electron microscopy characterization of epitaxial oxide multilayers fabricated by laser ablation on biaxially textured Ni

Microstructural characterization of rolling-assisted biaxially textured substrates (RABiTS) was conducted using high-resolution transmission electron microscopy (TEM) and high-resolution analytical electron microscopy (AEM). RABiT substrates with a multilayer configuration YSZ (0.2 μm)/CeO₂ (0.9 μm)/Ni (125 μm) were studied. The substrates were fabricated by epitaxial deposition of oxide layers using laser ablation on biaxially textured Ni substrates. High critical current density YBa₂Cu₃O_x thick films have been fabricated on such RABiT substrates and typically yield J_c values over 1 MA/cm². TEM examinations show that a reaction layer 10-40 nm thick is formed at the CeO₂/Ni interface. Detailed microstructural and chemical analyses indicate that the layer is epitaxial {001} nickel oxide on {001} Ni. The CeO₂ layer is found to consist of three distinct morphologies corresponding to the growth atmosphere during the deposition. The YSZ layer exhibited a columnar structure aligned along the [100] axis, with little or no orientation variation between the columns. The interface between the YSZ and CeO₂ layers is atomically sharp and neither interdiffusion of elements nor an interfacial reaction layer is observed. Implications of these results on processing are discussed.