DIRECT IMAGING OF SUBMICRON-SCALE DEFECT-INDUCED BIREFRINGENCE IN SRTIO3 BICRYSTALS

Using a near-held scanning optical microscope capable of quantitative polarimetry, we map the anisotropic strain fields associated with indi vidual submicron defects near the fusion boundaries of SrTiO3 bicrysta ls. Many defects exhibit unexpected spiral-shape strain patterns, whos e handedness is believed to be linked to the bicrystal synthesis proce ss. Direct observation of these defect-induced strain fields helps exp lain previously reported nonuniformity in the characteristics of high- temperature superconductor grain-boundary junctions fabricated on SrTi O3 bicrystals. (C) 1998 American Institute of Physics.