The effect of crystal growth conditions on the intergrowth of insulating and superconducting phases in the R-Ba-Cu-O systems

The complexity of the initial melts makes it difficult to grow reproducible high quality crystals of high-Tc superconductors. This difficulty is even further enhanced by the similarity of crystal paramters of phases existing in R-Ba-Cu-O systems. The latter leads quite often to the intergrowth of similar crystal phases and to the formation of heterophases 'crystals'. In this communication we consider mainly the effect of oxide compositions and temperature regimes, used in crystal growth, on crystallization of 123-compounds and some related phases. (orig.)