Chemical solution deposition of buffer layers

Chemical Solution Deposition (CSD) is a highly versatile and cost-effective method that is a very attractive and competitive alternative to physical vapor deposition techniques for the preparation of YBa₂Cu₃O_7-x (YBCO) coated conductors based on highly cube textured Ni-alloy substrates.

Therefore, La₂Zr₂O₇ (LZO) and CeO₂ thin layers, which are presently the buffer layer materials with the highest potential towards an realization of an all-chemically prepared YBCO coated conductor, have been deposited on Ni-5at%W substrates. New and very successful solution routes have been developed at the IFW Dresden that combine a low toxicity and ease in preparation. Epitaxially grown LZO buffer layers of high performance up to a thickness exceeding 200 nm have been reproducibly obtained showing a strong cube texture up to the surface, a crack-free surface morphology of low roughness, and, most importantly, a sufficient barrier function against Ni diffusion from the substrate. Strongly cube textured CeO₂ buffer layers have been successfully prepared on top of LZO to complete the buffer layer architecture for a subsequent deposition of YBCO.

Fig. 1	Fig. 2	Fig. 3

Fig. 1: Typical buffer layer architecture for chemical solution deposition

Fig. 2: Reflection high-energy electron diffraction pattern of the surfaces of a ~ 160 nm thick LZO buffer layer (left) and a ~ 60 nm thick CeO₂ buffer layer coated on top of a LZO layer (right) showing highly cube textured surfaces

Fig. 3: X-ray photoelectron spectroscopy depth profile of a ~ 160 nm thick LZO layer on Ni-5at%W showing no Ni diffusion into the layer

selected publications

Engel, S., Hühne, R., Knoth, K., Chopra, A., Kumar, N.H., Sarma, V.S., Santhosh. P.N., Schultz, L., Holzapfel, B.
Optimisation of single La₂Zr₂O₇ buffer layers for YBCO coated conductors prepared by chemical solution deposition
J. Crystal Growth 310 (2008) 4295-4300

Knoth, K., Hühne, R., Oswald, S., Molina, L., Eibl, O., Schultz, L., Holzapfel, B.
Growth of thick chemical derived pyrochlore La₂Zr₂O₇ buffer layers for YBa₂Cu₃O_7-x coated conductors
Thin Solid Films 516 (2008) 2099-2108

Knoth, K., Hühne, R., Oswald, S., Schultz, L., Holzapfel, B.
Detailed investigations on La₂Zr₂O₇ buffer layers for YBCO-coated conductors prepared by chemical solution deposition
Acta Mater. 55 (2007) 517-529

Engel, S., Knoth, K., Hühne, R., Schultz, L., Holzapfel, B.
An all chemical solution deposition approach for the growth of highly textured CeO₂ cap layers on La₂Zr₂O₇-buffered long length of biaxially textured Ni-W substrates for YBCO-coated conductors
Supercond. Sci. Technol. 18 (2005) 1385-1390

Knoth, K., Hühne, R., Oswald, S., Schultz, L., Holzapfel, B.
Highly textured La₂Zr₂O₇ buffer layers for YBCO coated conductors prepared by chemical solution deposition
Supercond. Sci. Technol. 18 (2005) 334-339