JOSEPHSON-JUNCTIONS DEFINED BY A NANOPLOUGH

We define superconducting constrictions by ploughing a deposited Alumi num film with a scanning probe microscope. The microscope tip is modif ied by electron-beam deposition to form a nanoplough of diamond-like h ardness which allows the definition of highly transparent Josephson ju nctions. Additionally, a dc superconducting quantum interference devic e is fabricated in order to verify the junction's behavior. The device s are easily integrated in mesoscopic devices as local radiation sourc es and can be used as tunable on-chip millimeter-wave sources. (C) 199 8 American Institute of Physics. [S0003-6951(98)04140-0].