Superconductivity and Microstructural Observation of Er0.5Y0.5Ba2Cu3O7-y

Abstract
The critical current density, J c, of Er0.5Y0.5Ba2Cu3O7-y was investigated in relation to its microstructure. An increase was observed in the J c of a sintered sample prepared from a mixture of YBa2Cu3O7-y and ErBa2Cu3O7-y with sintering time of up to 10 h at 930°C. The insufficiently sintered sample had a BaCuO2 network in the grain boundaries possibly caused by partial melting of the 1:2:3 compounds. This phase disappeared with increased sintering time, which relates to an endothermic reaction. It is considered that the increase in J c is due to an increase in the degree of sintering and to the disappearance of the highly resistive phase from the grain boundary.