Fabrication of YBCO Superconducting Tape by Metal Organic Chemical Vapor Deposition Method

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.

Formation identification of Y2BaCuO5and BaCeO3in MOCVD-processed YBCO films with Ce doping

“…YBCO films were grown through chemical reactions and surface diffusion on the substrates. The hot-wall-type MOCVD apparatus is described elsewhere in detail [11][12][13][14]. Films with 900 nm thickness were deposited at a temperature of 820 • C for 5 min under an oxygen partial pressure of 2.5 Torr.…”

The preparation of high-JcGd0.5Y0.5Ba2Cu3O7−δthin films by the MOCVD process

“…Due to its low vacuum requirement, relatively easy component adjustment and high production efficiency, MOCVD is adopted in this study to prepare the GdYBCO HTS films. To prepare high-performance HTS tapes to reduce costs, this paper studied the effect of the mole ratio of metal organic sources [22][23][24] on the performance of MOCVD-deposited GdYBCO thin films at appropriate heating currents [25][26][27].…”