Josephson Junctions Made of YBa2Cu3O7-x Superconducting Nanofilms

Conventional Josephson junctions are used to build superconducting quantum interference devices (SQUIDs) which are the most sensitive magnetic field sensors known. Today, SQUIDS are widely used in many different areas like medical and biological research and diagnostics, geophysics, non-destructive evaluation of materials and structures, or fundamental physics research. In recent years the highly anisotropic and unique intrinsic properties of YBa2Cu3O7- x superconducting nano-films allowed fabrication of a special type of Josephson junctions, so-called π-junctions, which are excellent candidates as building block for fast, low-dissipative superconducting digital electronics or quantum computation. For those reasons fabricating high quality and reliably Josephson junctions has been one of the priority areas of research in superconductivity. There are several well-established technologies to fabricate Josephson junctions made of YBa2Cu3O7-x superconducting nano-films. Here I will briefly describe two of the most important ones used to fabricate both conventional Josephson junctions and π-junctions.