GROWTH TWINS IN BI2CA1SR2CU2O8 SUPERCONDUCTOR SINGLE-CRYSTALS

Large-scale twin structures in single crystal Bi2Ca1Sr2Cu2O8 (2122) are reported for the first time. Symmetrical 90° (i.e., a-b) twins with a [110] type twin boundary were observed. A characteristic layer-growth morphology and jagged twin walls suggest that twin formation occurred layer by layer during crystal growth; i.e., the twins were growth twins. Hot-stage optical microscopy, x-ray diffraction, and electron microscopy results are discussed with reference to twin morphology.© 1990, Materials Research Society. All rights reserved.