SUSAN (Superconducting Systems Analysis) by Low Temperature Scanning Electron Microscopy (LTSEM)

Low-temperature scanning electron microscopy was used for spatially resolved investigations of both Josephson junctions and superconducting integrated circuits during their operation with a spatial resolution of about 1 mu m. Using single Josephson tunnel junctions of various geometries, the authors studied different dynamic states such as fluxon oscillations or unidirectional flux flow. With an integrated circuit consisting of a two-dimensional array of tunnel junctions and an RF detection circuit they investigated the RF properties of the coupling circuit and confirmed the existence of an impedance mismatch and a geometrical standing wave in the blocking capacitor. The studies of the dynamics of single Josephson tunnel junctions of various geometries showed a linear behavior (excitation of single cavity modes) if the boundary conditions dominate, and otherwise a nonlinear behavior (excitation of solutions).>