Superconductivity in Metamorphic Phases of Ba2ErCu3O7-δ

Abstract
We have confirmed the presence of three metamorphic phases of Ba2ErCu3O7-δ, which correspond to those of Ba2YCu3O7-δ. In addition to the high T c (92 K) orthorhombic phase, we obtained another orthorhombic phase and a tetragonal phase by rapid quenching. The former has a lower T c value of 50 K and the latter is semiconducting. Both the temperature dependence of resistivity and the T c value of each phase are similar to those of the yttrium system. It is likely that the common relation between the structure and superconducting properties exists for other rare earth systems as well.