Pressure-induced preferred orientation in YBa2Cu3O7-x high-Tc superconducting ceramics

The pressure-induced preferentially oriented structures developed in the process of preparing YBa2Cu3O7-x high Tc superconducting ceramics have been quantitatively measured by using the F- parameter method in X-ray powder diffraction and examined by scanning electron microscopy. The relations between oriented structures and the processing conditions such as pressure and heat treatments have been studied. Results show that the pressure-induced oriented structures which exist only in a thin surface layer have close relations with pressure as well as heat treatments which are carried out before the pressure is applied, but they do not affect the superconducting critical current densities of the samples in an obvious way