Planar current anisotropy and field dependence of Jc in coated conductors assessed by scanning Hall probe microscopy. (9th December 2016)

• Record Type: Journal Article
• Authors: Lao, M; Hecher, J; Sieger, M; Pahlke, P; Bauer, M; Hühne, R; Eisterer, M
• Is Part Of: Superconductor science & technology. Volume 30:Number 2(2017:Feb.)
• Publication Date: 2016-12-09
• Subjects: coated conductors -- trapped field -- critical current density -- scanning Hall probe microscopy -- vicinal films -- YBCO films; 74.25.Ha -- 74.25.Sv -- 74.25.Bd -- 74.72.-h; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/1361-6668/30/2/024004
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: The local distribution of the critical current density, J c, of coated conductors and YBa2 Cu3 O 7 − δ (YBCO) films on single crystalline substrate was investigated by scanning Hall probe microscopy. The high spatial resolution of the measurements enabled an assessment of dependence of the local J c on the local magnetic induction, B, and electric field, E . The derived J c ( B )-dependence agreed well with the global J c obtained from magnetization loops and provided values of J c at very low fields, which are inaccessible to magnetization and transport measurements. The anisotropic current flow within the film plane was investigated in YBCO films on miscut SrTiO3 substrates and a GdBa2 Cu3 O 7 − δ film on an MgO buffer layer prepared by inclined substrate deposition on a Hastelloy substrate. The c -axis currents calculated from the Hall maps were significantly larger than previously reported data obtained from direct transport measurements. The planar current anisotropy at 77 K was found to be highly influenced by the microstructure which can either deteriorate the current flowing across the ab -planes or cause enhanced pinning and increase the critical current flowing parallel to the ab -planes.