NOVELTY - An epitaxial article comprises a substrate having a textured metal surface; a single lanthanum metal oxide epitaxial buffer layer on the surface of the substrate; and an electromagnetically active layer on the single epitaxial buffer layer.    USE - The invention is used for providing a foundation for applying electromagnetically active layers (claimed). It is used with any electronic application in which epitaxy and/or crystallographic texture is important, and is specifically useful in forming high-temperature superconductor articles, such as superconducting wires or tapes. It is used in devices which include superconducting layers. It is useful in conjunction with an additional layer(s) in electromagnetic applications such as improved piezo-electrics, photovoltaic, tribological or fuel cells. The lanthanum metal oxide buffered metal substrates may be useful for giant magneto resistance (GMR), ferro-electric devices, electro-optic devices and for catalytic properties.    ADVANTAGE - For yttrium barium copper oxide (YBCO) coated conductors, the architecture of the inventive article provides improved reliability over previous superconducting architectures. The capping layer can help alleviate the lattice mismatch which can exist between the epitaxial buffer layer and the superconducting layer, and can improve the crystallinity and resulting performance of the superconducting article. It is possible to deposit a biaxially-textured superconductor with a high current densities (Jc) using a mechanically-robust epitaxial lanthanum metal oxide epitaxial buffer layer directly in contact with the metal substrate surface.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method of preparing an epitaxial article comprising providing a substrate with a textured metal surface; depositing a single lanthanum metal oxide epitaxial buffer layer on the surface of the substrate; and depositing an electromagnetically active layer on the single lanthanum metal oxide epitaxial buffer layer.    DESCRIPTION OF DRAWING(S) - The figure illustrates a schematic diagram showing superconductor layer architectures using textured-Ni or Ni-alloy substrates.