Melt-textured YBa2Cu3O7 samples were deformed under high-pressure high-temperature conditions (2GPa, 900 or 800C, 0.25h). During this treatment, the samples were in contact with annealed zirconia, to prevent O loss, in such a way that the orthorhombic superconductor phase was preserved at the end of the experiment. The deformed microstructure, investigated by transmitted electron microscopy, exhibited original features characterized by a very low twin density, a memory effect on dislocations shape and a non-classical faulted-loop distribution in the matrix. A mechanism based upon interactions between twins and gliding dislocations was proposed in order to explain the nucleation of the aligned loops.

Dislocation Configurations in Twin-Free Melt-Textured YBa2Cu3O7 Processed at High Pressure and Temperature. A.Joulain, F.Sandiumenge, N.Vilalta, T.Prikhna, A.V.Vlasenko, J.Rabier: Philosophical Magazine Letters, 2005, 85[8], 405-14