Vacancies

S.C. Speller  and C.R.M. Grovenor

Many of the most exciting advances in quantum technologies rely on very high quality resonant circuits fabricated in superconducting materials. Simple Al or Nb films can be used, but many of the most impressive results have been achieved with nitride films as the superconducting material because they offer greater stability to atmospheric attack and oxidation and so are less lossy. Previous work on TiN films has shown that the stoichiometry uniformity, oxygen content, resistivity, texture and residual strain all have a significant impact on resonance performance, and that film uniformity over large areas will become an important issue in future more complex circuit designs.  Although high quality VN and NbN thin films with excellent superconducting properties can be deposited, these materials have not been much tested for use in resonant circuits.  The objective of this project is to explore a wider range of new superconducting compounds and alloys for low loss resonant structures. The student, working closely with our industrial partners Oxford Instruments, will use the new thin film growth and characterisation facilities in the Centre for Applied Superconductivity to deposit and measure the properties of nitride thin films, and to assist in the testing of resonator performance with the quantum technology groups in both Physics and Materials Departments.

S.C. Speller and  C.R.M. Grovenor

New designs of high field magnets are combining high temperature superconducting materials with modern closed cycle cooling systems to create systems that are cheaper to operate than conventional machines.  Manufacturing these magnets will require processes for the fabrication of reproducible persistent mode joints between current leads and superconducting wires that can operate in significant background magnetic fields and also have the mechanical integrity to survive the thermal mismatches induced by warming and cooling operations.  The student, working closely with our industrial partners Oxford Instruments, will use the new facilities in the Centre for Applied Superconductivity to design novel thermomechanical processes to form joints between commercial wires and leads, and measure their properties over a wide range of applied fields and temperatures.  There will be opportunities for the student to spend time in the laboratories of Oxford Instruments, and to become an expert in the correlation of the microstructures formed by jointing processes and the superconducting performance of commercially-relevant devices.

S.C. Speller  and C.R.M. Grovenor

Superconducting magnet windings in particle accelerator applications are often subjected to high fluxes of energetic particles, and little is known about the effect on the superconducting properties of the lattice damage resulting from these interactions.  Now that superconducting coils are being designed for possible future fusion power systems, it is particularly important to develop a better understanding of these damage mechanisms.  This would be a CASE studentship in collaboration with a local company, Tokamak Energy, and with Oak Ridge National Laboratory in the USA and the University of Vienna.  The project will use advanced electron microscopy techniques to identify the key damage mechanisms in a range of different superconducting tapes and wires exposed to high energy particles and to correlate these with direct superconducting property measurements.

A. I. Coldea and Stephen Blundell

Novel superconducting materials are an unexpected rich playground to explore in order to identify the key parameters which make them good candidates for future practical applications. This project is to characterize the superconducting phase diagram as a function of temperature, magnetic fields and external strain in novel superconducting materials which come in various form from single crystals, powder and thin films. The project will be performed  using the high magnetic field facilities available in Oxford and elsewhere and will use a series of advanced  techniques for transport and thermodynamic measurements.