High Rate in situ YBa₂Cu₃O₇ Film Growth Assisted by Liquid Phase

High-rate (10 nm/s) in situ YBa₂Cu₃O₇ (YBCO) film growth was demonstrated by molecular beam epitaxy with electron beam co-evaporation at a system pressure of approximately 5 × 10^-5 Torr. To explain the phase stability observed, it is suggested that activated oxygen is generated in the process. Growth of very good YBCO, with a J_c of more than 2 MA/cm², is possible at this very high rate because the growth is in a liquid (Ba–Cu–O), which forms along with the YBCO epitaxy. This liquid seems essential for high J_c-YBCO film growth at very high in situ growth rates and may be essential for all high-rate processes, including postanneal ex situ processes.