Yanling Cheng

Preparation of

CeO₂ caped La₂Zr₂O₇ (LZO) buffer layers on cube-textured Ni5W substrates were fabricated by the method of chemical solution deposition(CSD). The orientation of both LZO film and CeO₂/LZO buffer layer was investigated using conventional XRD and X-ray four circle diffractometers, respectively. The results reveal that both the LZO film on Ni5W substrates and CeO₂ film on LZO buffer layer are grown epitaxially. The value of Full Width at Half Maximum (FWHM) of (111) Phi scan of CeO₂/LZO buffer layer is around 8^deg, and the FWHM of (200) omega-scan of CeO₂/La₂Zr₂O₇ buffer layer is 6.5^deg, indicating a good in-plan orientation of the as obtained buffer layers. It was observed by the high resolution SEM that the surface of LZO buffer layer is crack-free and very dense. The surface result observed by AFM indicates a very smooth CeO₂ surface with 5.9 nm of the root mean square roughness measured in an areas of 30 times 30 mum². AES depth profile results of CeO₂/LZO buffer layers shows that the deposited LZO film could effectively prevent the diffusion of Ni into the buffer layer.

{\rm CeO}_{2}/{\rm La}_{2}{\rm Zr}_{2}{\rm O}_{7}

This paper reports on the epitaxial growth of a La2Zr2O7 (LZO) buffer layer on the cube textured Ni-5 at.%W substrate with nitrates as the precursor salts. The solution stability and heat treatment routes were discussed in detail. In order to increase the stability of the nitrate solution, the dielectric constant of the solvent was discussed and alcohol amines were used as the chelating agent. The decomposition route of the precursor salt for each solution system was studied systematically before and after chelation. Subsequently, a cube-textured LZO epi-layer was obtained by rapid thermal annealing with the Full-Width-at-Half-Maximum (FWHM) values for in-plane and out-of-plane orientation found to be 7.0° and 5.0° respectively, demonstrating the feasibility of the nitrate solution route and the importance of the precursor properties for the epitaxial growth of the LZO layers.

Buffer Layers on Textured Ni5W Substrates by Chemical Solution Deposition Method

Electron backscatter diffraction (EBSD) was used for distinguishing crystallographic orientations and local lattice misfits of a La(2)Zr(2)O(7) (LZO) buffer layer epitaxially grown on a cube textured Ni-5.%W (Ni-W) substrate for a YBCO superconductor film. Orientation data were obtained from the LZO epilayer using low energy primary electrons (5keV) and from the Ni-W substrate by increasing the voltage to 15keV. In-plane and out-of-plane orientations of the LZO epilayer were revealed with respect to its Ni-W substrate. A strong {100} 〈011〉 rotated-cube texture in the LZO epilayer was formed on the {100} 〈001〉 cube-textured Ni-W substrates. LZO and Ni in-plane crystallographic axes are related by an expected 45° rotation. The step-misorientations and the local misfit strains between the LZO epilayer and the substrate were also analyzed.