Superconducting Circuits with Π-shift Elements

The topics presented in this thesis can be divided in three, roughly independent, parts: the Superconducting Network Model (Chapter 2), π-shift RSFQ circuits together with experimental aspects of the YBCO/Nb ramp-type Josephson devices (Chapters 3-4) and static π-shift circuits (Chapters 5-6). Chapter 2 attempts to formalize a Superconducting Network Model in a manner that is highly compatible with the methods and tools of standard microelectronic circuit analysis and design. First, a superconducting network is defined in the (φ,I) space while later practical aspects in the modeling of superconducting thin-film circuits are presented. The next two Chapters focus on π-shift circuits of the RSFQ family and measurement results obtained from such circuits manufactured in a hybrid YBCO/Nb technology. Additionally, various aspects of experimentation and fabrication of the circuits are given. In the last part, Chapter 5, a novel superconducting π-shift device is proposed. This device exhibits amplifier-like properties in the magnetic flux domain and can thus be used to build static (level-based) logic circuits operating with flux signals. Measurements on basic static π-devices are presented in Chapter 6.