Imaging Current Flow Distributions in Polycrystalline Bi2Sr2CaCu2Ox Superconductors by Magnetic Force Microscopy



Imaging of current transport at low temperatures; in a Bi-based thick-film superconductor is reported here. The approach is based on magnetic force microscopy (a scheme of the microscope is shown in the Figure) and is supplemented by finite element calculations of magnetic fields induced by current flow. The results (see cover) show that the current flows mainly in thin layers close to the grain boundaries of the superconductor.