Magneto-optical imaging of transport currents in YBa/sub 2/Cu/sub 3/O/sub 7-x/ on RABiTS/sup TM/

Two YBa/sub 2/Cu/sub 3/O/sub 7-x/ (YBCO) on RABiTS/sup TM/ conductors with high J/sub c/ (0 T, 77 K) values of 2.3 and 2.4 MA/cm/sup 2/ were scribed by laser cutting to constrict supercurrent flow. On one of these tracks, magneto-optical (MO) imaging of the self-field produced by a transport current directly demonstrates the percolative nature of the current flow. Using backscattered electron Kikuchi pattern (BEKP) analysis, we have found that Ni grain boundaries (GBs)>5/spl deg/ generally introduce GBs in the YBCO that have lower J/sub c/ values than the intra-grain.