Phase transformation in Y-Ba-Cu-O superconductors

Abstract

Pellets of single phase Y1Ba2Cu3O7 were annealed in air over a temperature range from 400 to 800°C followed by rapid quenching to room temperature. An X-ray diffraction technique was used in order to determine the effect of temperature on the crystal structure and lattice parameters of the single phase Y1Ba2 Cu3O7. The orthorhombic structure (Superconducting phase) has lattice parameters of a = 3.8191 A0, b = 3.882 A0, and c = 11.7055 A0, and the tetragonal structure (non-superconducting phase) has a lattice parameters of a = 3.849 A0, and c = 11.7102 A0. The tetragonal-to-orthorhomic transformation occurs in the narrow temperature range of 490-500°C, and it has nucleation and growth transformation characteristics.