No abstract

YBCO films for coated conductors (CC) were fabricated by a metal organic chemical vapor deposition (MOCVD) system of hot-wall type using a single source. The deposition condition was optimized using (100) SrTiO 3 single crystal substrates in a steady state, and then the substrate was replaced by moving IBAD template (CeO 2 /IBAD-YSZ/stainless steel) of 40 cm/hr. Two different types of IBAD templates with thin CeO 2 and thick CeO 2 layers were used. The mole ratio of MO source was Y(tmhd) 3 : Ba(tmhd) 2 : Cu(tmhd) 2 = 1 : 2 1 : 2 9, and the YBCO films were prepared at the deposition temperatures of 780 890 C. The a-axis growth was observed together with the c-axis growth up to 830 C, while the c-axis growth became dominant above 830 C. The top surface of the c-axis film was fairly dense and crack-free. In case of the YBCO film with a 2.2 m thickness deposited on the SrTiO 3 substrate at 860 C, the deposition rate was as high as 0.37 m min. The critical current and critical current density of the film was 104 A/cm-width and 0.47 MA cm 2 , respectively. The YBCO film deposited on the IBAD template with a thin CeO 2 layer showed a low critical current of 2.5 A/cm-width, while the YBCO film deposited on the IBAD template with a thick CeO 2 layer showed a higher critical current of 50 A/cm-width. It indicates that the stable buffer layer at high deposition temperature is needed for the MOCVD process.Index Terms-CeO 2 layer, critical current, IBAD template, MOCVD, SrTiO 3 substrate, YBCO film.

No abstract