Superconducting device having an extremely short superconducting channel formed of extremely thin oxide superconductor film

A superconducting device comprising:

• a substrate,
• an oxide superconductor thin film deposited on a deposition surface of said substrate, said superconductor thin film defining a superconducting channel therein;
• a source electrode and a drain electrode formed on said oxide superconductor thin film at opposite ends of said superconducting channel, so that a superconducting current can flow through said superconducting channel between said source electrode and said drain electrode, and a gate electrode formed on a gate insulator layer on said superconducting channel so as to control superconducting current flow through said superconducting channel, said gate electrode being provided by a thin film which has been formed perpendicular with respect to said gate insulator layer whereby, in a direction of current flow through said superconducting channel between said source and drain electrodes, said gate electrode having a gate length of no more than 100 nm.