The effect of water pressure on the texture and morphology of MOD-YBCO films on buffered metal substrates

The influence of water pressure in the metal-organic deposition (MOD) method on the texture and morphology of YBa2Cu3O7-X (YBCO) films grown on buffered metal substrates was investigated. The water pressure was varied from 4.2% to 10.0%, with the other process parameters, such as annealing temperature and oxygen pressure, kept constant. In this work, a YBCO precursor solution was prepared using a fluorine-free Y and Cu precursor solution with the addition of Sm. MOD-YBCO films were fabricated by continuous slot-die coating and calcination, followed by high temperature annealing. Using x-ray diffraction analysis, unreacted phase peaks, such as BaF2 peaks, were found in the samples made at a water pressure of 4.2%; however, the BaF2 peak intensity was much reduced as the water pressure was increased. The higher water pressure of about 10.0% in this experiment led to the poor crystallinity of MOD-YBCO films, possibly due to the fast reaction with the supplied water vapor. Meanwhile, the morphologies of the YBCO films were not much different from each other in the range of water pressure of this work. The maximum critical current density of 3.8 MA cm-2 was obtained when the sample was made at the water pressure of 6.2% and the annealing temperature of 780 deg. C.