Analysis of Dislocations in Y-Ba-Cu-O Superconductors.

Transmission electron microscopy was used to characterize dislocations in Y-Ba-Cu-O superconductors. Dislocations which are rarely seen in the sintered YBa sub 2 Cu sub 3 O sub (7-delta) superconductor are found to be abundant in grain-oriented samples fabricated by the Melt-Textured-Growth method. The density of dislocations is estimated to be about 10 sup 9 ~ 10 sup (10) lines/cm sup 2 which is 2~3 orders of magnitude increased over that for the sintered sample. An analysis using the g bar for . b bar for = O criteria unambiguously proves that the Burgers vectors of the dislocations are of [100] or [010] type with the slip plane being the (010) or (100) plane. These results imply the possibility of using slip deformation to increase the defect density and influence the flux pinning behavior.