Improved morphological and barrier properties of lanthanum zirconium oxide buffer layers obtained by chemical solution deposition for coated conductors

Abstract

Lanthanum Zirconium oxide buffer layers with a narrow compositional window of LaZr_xO_y (x = 0.7–1.3) have been grown on textured NiW substrates by chemical solution deposition (CSD). X-ray diffraction analysis indicates that a single epitaxial LZO phase with well bi-axial texture can be obtained in a narrow compositional range of x = 0.7–1.1 in LaZr_xO_y, while higher x value yields incompletely (00l) textured films. Morphological and barrier properties have been investigated by atomic force microscopy (AFM) for as-grown samples and X-ray diffraction (XRD) for the re-annealed samples in an oxidizing atmosphere. AFM images indicate a dramatic improvement of surface plateness for LaZr_xO_y (x > 1) film with respect to LaZr_xO_y (x = 1) with standard composition. Barrier properties of LZO show an obvious increasing trend with the increase of x value in LaZr_xO_y, which may be related to the change of the intrinsic oxygen diffusion coefficient for buffer layers with different compositions. The improvement of surface planeness and barrier property in buffer layer is the key towards obtaining epitaxial YBCO films with a higher critical current density. Therefore, the present result demonstrates a promising route for producing low-cost and high-performance coated conductors.