The role which was played by extended defects, especially {111} twins, in anomalous grain growth was investigated. It was found that twinning alone did not trigger anomalous grain growth in this ceramic. In truly polycrystalline material, the critical current density was reduced by several orders of magnitude at 77K; due to the presence of grain boundaries. High-resolution transmission electron microscopy, combined with image simulation, was used to analyse the structures of the crystal defects.

Extended Crystal Defects in Perovskite Related Materials: Characterisation and Technological Relevance. O.Eibl: Radiation Effects and Defects in Solids, 1999, 151[1-4], 983-95