Transmission Electron Microscopy of Superconducting A15 Compounds

Abstract

Unlike many other branches of materials science, there have been relatively few applications of electron microscopy in the study and development of superconducting materials, the principal application being in the study of microstructure in ductile-superconductors such as Nb-Ti and Nb-Zr. However, in recent years this trend has changed, and TEM is now being applied to technologically important high transition temperature compounds with the A15 structure, e.g., Nb3Sn, Nb3Ge, V3Ga, V3Si. Main areas of study are the role of grain boundary structure and segregation on critical currents, nature of the radiation damage, and the possibility of directly imaging the flux line lattice. Analytical scanning transmission electron microscopy (STEM) is now increasingly being used to investigate the first two areas mentioned above. However, a direct imaging of flux line lattice remains the biggest challenge in this field. In this paper the author's studies of superconducting compounds using TEM are briefly reviewed.