CROSS-SECTIONAL HIGH-RESOLUTION TRANSMISSION ELECTRON-MICROSCOPE STUDIES OF SUPERCONDUCTING OXIDE THIN-FILMS OF THE BI-SYSTEM

Structures of artificial Bi-O/ Sr-Ca-Cu-O multilayered films with a designed period of c=3.7 nm have been examined by a cross-sectional TEM method. The modulated structure similar to bulk BSCCO can be seen in both samples cooled in oxygen, which are superconductors of Tc(zero)= 10-30 K, and samples cooled in vacuum, which are not superconductors. In the films, Bi atoms frequently shift from the standard position of bulk BSCCO. In the most of the grains a and b axes of the films are parallel to <100> of the MgO substrate. The epitaxial growth is discussed considering that both Bi-O layers and MgO have the rock salt type structure. © 1990, The Japan Institute of Metals. All rights reserved.