Optimization in the preparation of the YBa2Cu3O7-δ compound using BaCO3 and BaO2 reagents

The traditional superconductor YBa2Cu3O7-δ (Y123) has an orthorhombic crystalline structure with spatial group Pmmm and its critical temperature is 90K. The literature reports the use of reagent BaCO3 for the preparation by the solid state reaction which requires one calcination and two thermal treatments in oxygen flow at 950oC. In this work we report the comparison in the preparation of Y123 using the BaO2 reagent as another possibility for preparation; in this case we have used only two thermal treatments in oxygen flow at 950oC; therefore reducing the costs in preparation. The powder XRD pattern of samples prepared with BaO2 confirm a well crystallized phase an the diffraction lines of the main phase can be indexed with an orthorhombic unit cell. The ac susceptibility measurement in the range 5-100 K using a Quantum Design (SQUID) magnetometer for two samples confirms the superconductor behavior with critical temperature Tc ≅ 91 K. The critical temperatures for these systems were found taken account the derivatives of the susceptibility curves. Scanning Electron Microscopy (SEM) confirms the good behavior of the grains corresponding to both methods. (orig.)