High‐resolution electron microscopy of high‐temperature superconductors

We review recent results obtained at Northwestern using high‐resolution electron microscopy to study high‐temperature superconductors. While in general these materials form large, very perfect single crystal grains which display very few imperfections, there is also evidence of slip defects, amorphous regions, and order‐disorder transformations. We also report that the gadolinium‐based superconductors and in one case yttrium‐based superconductors show evidence for some copper solid solubility in the form of copperrich planar defects. The structure of a metastable trigonal polytype is also reported, as are the effects of electron beam and water vapor damage to the materials.