Zirconium Doped Yttria as a Buffer Layer for GdBCO Superconductors Deposited by Chemical Solution Deposition

A simple method is reported here to deposit zirconium doped ytrria (Y2O3-ZrO2 (YZrO)) as a composite buffer layer on Hastelloy C-276 substrate using chemical solution deposition (CSD) at room temperature. Yttrium acetate, zirconium acetate, and diethanolamine in methanol were used as precursors at two different concentrations (0.1 and 0.2 M). Films were deposited by dipping 20 times that resulted in a film thickness of similar to 440 nm at 0.1 M and similar to 1.26 mu m at 0.2 M concentration. Substrate surface roughness (rms) reduced greatly from 50 nm to similar to 3.8 nm over a 10 x 10 mu m(2) area, from films deposited at 0.1 M concentration, indicating a smooth buffer layer to deposit c-aligned ion-beam assisted deposition (IBAD) MgO, and sputtered LaMnO3 (LMO). From Photoelectron spectroscopic data, no diffusion of substrate metal ions was found in the buffer layer, while X-ray diffraction data indicated amorphous or non-crystalline nature of the film. After YZrO deposition, MgO was deposited using IBAD, LMO was deposited using sputtering and then GdBCO was deposited using reactive co-evaporation and reaction (RCE-DR). Good out-of-plane and in-plane textures with strong c-axis alignment observed from X-ray study indicated that LMO/MgO/YZrO and GdBCO/LMO/MgO/YZrO stack are planar and stacked properly. The critical current (lc) obtained from the GdBCO/LMO/MgO/YZrO multilayer structure is 400 A/cm at 77 K and self-field.