HIGH-TEMPERATURE X-RAY-DIFFRACTION STUDIES OF THE COMPOUND YBA2CU3OX

Ambient and high temperature X-ray diffraction methods were used to determine the unit cell parameters of the orthorhombic and tetragonal phases of the YBa2Cu3Ox compound, as a function of oxygen stoichiometry and temperature. The total oxygen content was obtained by the thermogravimetric method (TGA) by determining the weight loss in hydrogen up to 1000 degrees C. Reduction reactions in hydrogen were also performed in situ using a high temperature X-ray unit. Using the TGA method the oxygen content in the structure was obtained by weight loss in 100% oxygen. Thermal expansion coefficients of the lattice parameters were determined for both orthorhombic and tetragonal materials with different, constant x values.