Computer simulations were used to determine the most probable grain boundary misorientation distribution in model polycrystalline superconductors. The misorientation distribution in such a material was expected to govern the critical current density for macroscopic transport. The calculations were performed by simulating model polycrystals, and then determining the grain boundary misorientation distribution. Such distributions were calculated for random materials with cubic, tetragonal or orthorhombic symmetry. Because most high-temperature superconductors were tetragonal or pseudo-tetragonal, the effect of macroscopic uniaxial and biaxial grain orientation textures upon the grain boundary misorientation distribution was determined for tetragonal materials. It was found that a macroscopic texture markedly altered the grain boundary misorientation distribution. The fraction of low-angle boundaries increased significantly in the presence of an uniaxial or biaxial texture. The present results were expected to be important in correlating macroscopic transport with the grain orientation textures which were determined by means of X-ray diffraction.

A.Goyal, E.D.Specht, D.M.Kroeger, T.A.Mason: Applied Physics Letters, 1996, 68[5], 711-3