Full text loading...
TEM micrograph of a cross section of the GB region in a 24°  tilt Ba-122 film which confirms that the grains are epitaxial and c-axis oriented. The HRTEM image (a) is viewed parallel to the GB in longitudinal section parallel to the (001) planes. The (001) planes are well aligned across the GB. A lower magnification image from a region with a single grain orientation (b) shows that the film is of uniform thickness. The selected area diffraction pattern of the Ba-122 film along the  zone axis is shown in (c) together with the corresponding SAD pattern for the substrate (d). The SAD patterns show that the Ba-122 film is single-crystal, c-axis oriented, and epitaxially related to the substrate.
Irreversibility field and upper critical field defined by the 10% and 90% points of on resistance curves across a 6°  tilt GB and its neighboring grain with field applied perpendicular to the film. Inset: resistive transitions up to 35 T across the GB.
(a) LTLSM image scanned in steps of a 6°  tilt bicrystal taken at 12 K and 0.25 T with bias current of 39 mA which generated across the bridge. It shows a 2D map of induced by transport current along the bridge across the GB. E is enhanced by a factor of 23 at the GB as compared to the intragranular E. (b) MO image of a 9° bicrystal with computed streamlines (yellow) of the magnetization current calculated from the Bean model (Ref. 27). The MO image was taken after cooling to 6 K in a perpendicular field of 120 mT and then reducing the field to zero.
Dependence of the critical current density across GBs (12 K, 0.5 T) as a function of the misorientation angle . The inset shows summary data from Ref. 1 for YBCO GBs.
Comparative field dependencies of the critical current density across GB and in the grains for (a) 6° and (b) 24° bicrystals at 12, 14, and 16 K. The gap between and diminishes as the field increases.
Article metrics loading...