Josephson junctions defined by a nanoplough

We define superconducting constrictions by ploughing a deposited Aluminum film with a scanning probe microscope. The microscope tip is modified by electron-beam deposition to form a nanoplough of diamond-like hardness which allows the definition of highly transparent Josephson junctions. Additionally, a dc superconducting quantum interference device is fabricated in order to verify the junction’s behavior. The devices are easily integrated in mesoscopic devices as local radiation sources and can be used as tunable on-chip millimeter-wave sources.