Synthesis of YBaSrCu₃O_y under High Oxygen Pressure

Abstract

The sintered YBaSrCu₃O_y was treated at 300-600°C under high oxygen pressure (PO₂=20600atm). The samples showed the decrease of orthorhombic distortion with decreasing the annealing temperature. Below 350°C under 100atm, orthorhombic YBaSrCu₃O_y transformed to tetragonal phase with the increase of oxygen content ( y>7.0). The superconductive transition temperature was almost comparable to tho orthorhombic YBaSrCu₃O_y.