Growth of rare-earth zirconates-based pyrochlore buffer layers on YSZ for YBCO-coated conductors via chemical solution deposition

Epitaxial films of rare-earth zirconates, RE2Zr2O7 (RE = La, Nd, Sm and Gd) were grown on yttrium stabilized zirconia (100) single crystal substrates using metal-organic deposition. A precursor solution of 0.25-0.40 M concentration of total cations was spin-coated on yttrium stabilized zirconia substrates and crystallized at 1000 degrees C for 3 h in Ar-4%H-2 after calcination at 500 degrees C for 1 h. X-ray diffraction studies showed that the resulting pyrochlore RE2Zr2O7 films were highly textured with cube-on-cube epitaxy. Atomic force microscopy investigations revealed that the surfaces of La2Zr2O7, Nd2Zr2O7 and Sm2Zr2O7 films had a fairly dense and smooth microstructure without cracks and porosity, but that voids could be seen on the surface of the Gd2Zr2O7 film. Optical microscopy measurements confirmed that the Gd2Zr2O7 precursor solution showed poor wetting behavior on the substrate. It was concluded that the Nd2Zr2O7 and Sm2Zr2O7 films could be potentially used as buffer layers for YBa2Cu3O7-delta coated conductors.