Electron beam co-evaporation of Y-BaF2-Cu precursor films for YBa2Cu3O7-y coated conductors

Y-BaF2-Cu precursor films for Y-Ba2CU3O7-y (YBCO) coated conductors have been deposited on both uncoated nickel and Rolling Assisted Biaxially Textured Substrate (RABiTS (TM)) tapes by electron beam coevaporation. The water partial pressure was kept constant at 1 x 10(-5) Ton. during the deposition in order to control the oxygen content in the precursor films. Rutherford backscattering spectroscopy measurements indicate an average composition of Y:Ba:Cu of 1.05:2.10:3.0 with a standard deviation of less than 2.0%. This result was obtained for both moving and stationary tapes. The thickness variation of such precursor films is less than 2.5% over lengths of up to 1 m. Films up to 5 mum thick have been deposited on a stationary tape. An end-to-end J(c) of 100 000 A cm(-2) from a 1 m length of RABiTS (TM) sample has been obtained with the highest J(c) of 774 000 A cm(-2) in a short section within the tape. The present research demonstrates a possible route for industrial scale-up using electron beam coevaporation of YBCO precursors.