Metal Organic Deposition of Epitaxial Y123 Films Using a Low-Cost Vacuum Technique

Epitaxial YBa/sub 2/Cu/sub 3/O/sub 7/ (Y123) films were obtained by metal-organic deposition (MOD) using a simple, low-cost vacuum technique without gas flowing. The total pressure and oxygen partial pressure in the furnace were controlled to be 10 kPa and 10 Pa, respectively, by evacuation with a rotary pump followed by refilling with a mixture of O/sub 2/ and N/sub 2/ (O/sub 2/ content: 1000 ppm). XRD analyses exhibited that c-axis-oriented epitaxial Y123 films have successfully been obtained on CeO/sub 2/-buffered YSZ (100) (CbZ) and CeO/sub 2/-buffered sapphire (012) (CbS) substrates. In-plane alignments of these films were as high as that of the CeO/sub 2/ buffer layer. The film on the CbZ demonstrated a high critical current density J/sub c/ of /spl sim/2.1 MA/cm/sup 2/ at 77 K all over the film; the fluctuation of J/sub c/ being within /spl plusmn/10% of the average. Inductive T/sub c/ measurement showed a very sharp peak with T/sub c/=90.5 K. Inductive-J/sub c/ and T/sub c/ of the Y123 film on CbS were 1.1 MA/cm/sup 2/ and 89.6 K, respectively, whereas the T/sub c/ of the Y123 film on LaAlO/sub 3/ was lower than 77 K owing to the occurrence of the a-axis grains.