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

Abstract

The influence of water pressure in the metal–organic deposition (MOD) method on the texture and morphologyof YBa2Cu3O7−X (YBCO) films grown on buffered metal substrates was investigated. The water pressure wasvaried from 4.2% to 10.0%, with the other process parameters, such as annealing temperatureand oxygen pressure, kept constant. In this work, a YBCO precursor solution was preparedusing a fluorine-free Y and Cu precursor solution with the addition of Sm. MOD-YBCOfilms were fabricated by continuous slot-die coating and calcination, followed by hightemperature annealing. Using x-ray diffraction analysis, unreacted phase peaks, such asBaF2 peaks, were found in the samples made at a water pressure of 4.2%; however, theBaF2 peak intensity was much reduced as the water pressure was increased. The higher waterpressure of about 10.0% in this experiment led to the poor crystallinity of MOD-YBCOfilms, possibly due to the fast reaction with the supplied water vapor. Meanwhile, themorphologies of the YBCO films were not much different from each other in therange of water pressure of this work. The maximum critical current density of3.8 MA cm−2 was obtained when the sample was made at the water pressure of 6.2% and the annealing temperatureof 780 °C.