Pj. Hirst et al., THE MICROSTRUCTURE OF THE TWIN TO TWEED TRANSITION IN ALUMINUM SUBSTITUTED YBA2CU3O7-DELTA SINGLE-CRYSTALS, Physica. C, Superconductivity, 235, 1994, pp. 371-372
Single Crystals of the superconductor YBa2Cu3O7-partial derivative hav
e been grown with controlled amounts of aluminium doping just below th
e twin to tweed transition (1 and 1.5 cationic%) and are examined usin
g single crystal x-ray diffraction and TEM. The nature of the twinning
changes from well defined twins and colonies in undoped crystals to a
n interpenetrating twin morphology as the tweed transition is approach
ed.