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 times; 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 Jc 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 Jc-YBCO film growth at very high in situ growth rates and may be essential for all high-rate processes, including postanneal ex situ processes.
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We acknowledge discussions with many colleagues, including Prof. J. MacManus-Driscoll, Prof. T.H. Ge-balle, Prof. Prof. M.R. Beasley, Dr. Y. Shiohara, Dr. J. Storer, Dr. R. Feenstra, Dr. W. Wong-Ng, and Dr. L.P. Cook, and the financial and equipment assistance of 3M in the initial stages and the United States Department of Energy under Contract No. 19XTA478C through 2001. We acknowledge the support of the DoD/Air Force Multidisciplinary University Research Initiative under the University Wisconsin Air Force Grant No. F49620-01-1-0464, Stanford University subgrantee 412F064 in the later stages.