High critical current YBCO coated conductors based on IBAD MgO P.N. Arendt * , S.R. Foltyn, L. Civale, R.F. DePaula, P.C. Dowden, J.R. Groves, T.G. Holesinger, Q.X. Jia, S. Kreiskott, L. Stan, I. Usov, H. Wang, J.Y. Coulter Superconductivity Technology Center, Los Alamos National Laboratory, P.O. Box 1663, MS K763, Los Alamos, NM 87545, USA Received 29 October 2003; accepted 2 December 2003 Available online 1 June 2004 Abstract This report describes recent developments of second-generation Y 1 Ba 2 Cu 3 O 7d (YBCO) coated conductors deposited on biaxially textured MgO templates. The materials system architecture implemented to achieve high critical currents in YBCO films is described. The average full-width at half maximum (FWHM) in-plane texture obtained for MgO films processed on meter-length tapes is 7°, while that for the YBCO films is 3°. The best YBCO in-plane values approach 2° and the out-of-plane values approach 1°. Critical currents (1 cm wide tapes, 75 K, self field) have attained 423 A for 7 cm length and 233 A for 50 cm length tapes. Ó 2004 Elsevier B.V. All rights reserved. PACS: 74.72.B; 74.80.B; 81.15.)z Keywords: YBCO coated conductor; Ion-beam assisted deposition; Biaxial texture 1. Introduction Ion-beam assisted deposition of MgO (IBAD MgO) [1,2] is a promising approach for fabricating long-length template films for high critical current YBCO coated conductors [3]. Its promise lies in the fact that very good biaxial texture can be ob- tainedwithfilmsonly10nmthick[4].Becauseitis much thinner than other high quality IBAD tem- plates (e.g. yttria-stabilized zirconia (YSZ) is 500–700 nm thick) [5,6], IBAD MgO requires additional layers not needed when IBAD YSZ is implemented. Fig. 1 is a cross-section transmission electron micrograph (TEM), which provides a comparison of the non-superconducting layers presently needed to successfully fabricate high quality YBCO films using these two templates. In both cases, a buffer layer is required to ameliorate lattice mismatch and potential deleterious interfa- cial reactions between the IBAD and the YBCO films. Fig. 1(a) illustrates IBAD YSZ and its accompanying buffer (CeO 2 ) film. In Fig. 1(b) al- though the IBAD MgO is much thinner than the IBAD YSZ, several thin, non-superconducting layers are present in addition to the SrTiO 3 buffer. These extra layers have differing functions, which either exist in the IBAD YSZ or are not required * Corresponding author. Tel.: +1-505-665-8358; fax: +1-505- 665-3164. E-mail address: arendt@lanl.gov (P.N. Arendt). 0921-4534/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.physc.2003.12.074 Physica C 412–414 (2004) 795–800 www.elsevier.com/locate/physc