Phase changes in Y1Ba2Cu3O7-xinduced by Fe2O3and V2O5dopants

Abstract
Thermodynamic calculations show that the tetragonal phase of Y1Ba2Cu3O7-x is stabilised by Fe2O3 dopants, while the superconducting orthorhombic phase is favoured by V2O5 because of its high oxygen potential. Measurements made with varied dopant levels support these calculations. V2O5 also has a densifying effect, most likely via liquid-phase sintering, with little detriment to the superconducting properties.