Coating processes for YBa2Cu3O7-xsuperconductor by metalorganic deposition method using trifluoroacetates

YBa 2 Cu 3 O 7- x (YBCO) films prepared by a metalorganic deposition method using trifluoroacetats (TFA-MOD method) with spin coating have excellent properties: a critical current density ( J c ) of over MA cm -2 (77 K, 0 T) and a critical temperature of over 92 K. However, films prepared by spin coating shrink at lower spinning rates or have striation at higher spinning rates. Both shrunk films and films with striation have low J c . Moreover, even if striation is not observed by scanning electron microscopy scale observation, a structure containing pores was confirmed by transmission electron microscopy. Such pores are considered to result in a low J c of the films. To avoid such problems we adopted dip coating as the coating process in the TFA-MOD method. The dipped YBCO films have excellent J c compared to the spun films. A typical dipped YBCO film of 0.25 µm in thickness on LaAlO 3 single-crystalline substrate has a transport J c of 5.3 MA cm -2 (77 K, 0 T).