Double disordered YBCO coated conductors of industrial scale: high currents in high magnetic field. (9th October 2015)

• Record Type: Journal Article
• Authors: Abraimov, D; Ballarino, A; Barth, C; Bottura, L; Dietrich, R; Francis, A; Jaroszynski, J; Majkic, G S; McCallister, J; Polyanskii, A; Rossi, L; Rutt, A; Santos, M; Schlenga, K; Selvamanickam, V; Senatore, C; Usoskin, A; Viouchkov, Y L
• Is Part Of: Superconductor science & technology. Volume 28:Number 11(2015:Nov.)
• Publication Date: 2015-10-09
• Subjects: superconducting -- thin films -- laser -- deposition -- high temperature -- superconductors; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/0953-2048/28/11/114007
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: A significant increase of critical current in high magnetic field, up to 31 T, was recorded in long tapes manufactured by employing a double-disorder route. In a double-disordered high-temperature superconductor (HTS), a superimposing of intrinsic and extrinsic disorder takes place in a way that (i) the intrinsic disorder is caused by local stoichiometry deviations that lead to defects of crystallinity that serve as pining centers in the YBa2 Cu3 O x − δ matrix and (ii) the extrinsic disorder is introduced via embedded atoms or particles of foreign material (e.g. barium zirconate), which create a set of lattice defects. We analyzed possible technological reasons for this current gain. The properties of these tapes over a wider field-temperature range as well as field anisotropy were also studied. Record values of critical current as high as 309 A at 31 T, 500 A at 18 Tm and 1200 A at 5 T were found in 4 mm wide tape at 4.2 K and B perpendicular to tape surface. HTS layers were processed in medium-scale equipment that allows a maximum batch length of 250 m while 22 m long batches were provided for investigation. Abnormally high ratios (up to 10) of critical current density measured at 4.2 K, 19 T to critical current density measured at 77 K, self-field were observed in tapes with the highest in-field critical current. Anisotropy of the critical current as well as angular dependences of n and α values were investigated. The temperature dependence of critical current is presented for temperatures between 4.2 and 40 K. Prospects for the suppression of the dog-bone effect by Cu plating and upscale of processing chain to >500 m piece length are discussed.