Synthesis of T1-System Monophase Superconductors under Oxygen Pressure and Its High Pressure Effect

Effect of oxygen pressure on the preparation of TI-system superconductors at pressure 0～3 MPa is reported. Under the same sintering temperature and in the same duration, the phase fractions and Tc as well as the weight loss are found to depend directly on the oxygen pressure. When the oxygen pressure is higher than 1.45 MPa, we can get pure 2212 phase super conductors. The samples contain both 2212 and 2223 phase if the oxygen pressure is 0.9～1.45 MPa. Pure 2223 phase samples can be obtained when the oxygen pressure is 0.25～0.9 MPa. The high pressure effect on samples with 2223 phase and 2212 phase also was studied. The dTc0/dp for sample with 2223 phase is 4 K/GPa, and 2 K/GPa for sample with 2212 phase under pressure 0～0.52 GPa. The sample with 2223 phase has stronger pressure effect than their sample with 2212 phase.