AN ELECTRON MICROSCOPE INVESTIGATION OF FLUX PINNING CENTRES IN SUPERCONDUCTING V3GA TAPES

The defect structure of V3Ga tapes produced by a solid-state diffusion process, has been studied by electron transmission using a microscope with an acceleration voltage of 500 kV. The only defects found in appreciable numbers are grain boundaries. It is concluded that these are the most important flux pinning centers. The amount of lossless current which can be carried by these tapes in the superconducting state is correlated with the grain size. © 1969.