Josephson junctions are an integral component of superconducting electronics because of
their non-linear response and have not only been incorporated into a number of devices
including superconducting quantum interference devices (SQUIDs) to create highly sensitive
magnetometers and Josephson flux vortex transistors (JVFTs) to make fast-switching, high
gain transistors but also into experiments to resolve the unexplained pairing mechanisms in
As such, chapter 2 describes the results of an investigation into the pairing mechanism of the
infinite layer superconductor Sr1-xLaxCuO2 using a single Josephson junction. The main result
of this was that observations of zero bias conductance peaks (ZBCP) strongly suggest that
SLCO superconductors are d-wave superconductors. This also contradicts many previous
reports which concluded that SLCO superconductors are s-wave superconductors.
Chapter 3 describes the results of measurements of YBa2Cu3O7-δ Josephson junction arrays.
The results of this showed that the device had periodical behaviour at temperatures close to Tc
with a periodicity of 1.8 mA or 12 μT. Moreover, it was found that this device could also
operate as a Josephson vortex flow transistor (JVFT) which produced gains as high as 19.28
± 0.03 at 77 K. In addition, switching behaviour was also found. Therefore, the record high
current gains found at 77 K and above, as well as the switching behaviour make this device
highly suitable for applications as a superconducting transistor
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.