Antiphase domain boundaries in the superconducting phase of Y-Ba-Cu-O system.

Transmission electron microscopy examination of the superconducting phase of Y-Ba-Cu-O system reveals the presence of dense antiphase boundaries. The structure of the superconducting phase was determined to be orthorhombic with space group Pm2m. The orthorhombic a- and b-axes are found to alternate across the antiphase boundary which runs parallel to the {110} direction.