Preparation of YBaCuO film on a MgO substrate by chemical vapor deposition at 650°C

YBaCuO films were prepared on a MgO(100) single-crystal substate at 650°C by a chemical vapor deposition method. The films were fabricated at various oxygen partial pressures of 0.516 Torr, 0.121 Torr, 0.0126 Torr and 0.009 Torr. Superconductivity above liquid nitrogen temperature ( T c,0 =87 K and T c,onset =91 K) was obtained for the film prepared at 0.0126 Torr. J c (77 K, 0 T) was measured as 3×10 4 A/cm 2 . A two-dimensionally well-aligned microstructure was observed for the film prepared at 0.0126 Torr.