Dr Stuart Wimbush
Dr Stuart Wimbush has expertise in the following areas.
Coated conductor development
In collaboration with American Superconductor Corporation and other superconducting wire manufacturers, Stuart works to characterise, develop and understand the performance of the superconducting YBCO layer that forms the heart of second generation coated conductor tapes.
The aim of the work is improved tape performance through nanostructural engineering, particularly at low temperatures and intermediate magnetic fields, which form the present application targets. The measure of performance is the critical current density at which superconductivity breaks down, which is of the order of 10,000 times the current capacity of copper.
Superconductivity and magnetism
Stuart’s longest-running academic interest has been in the interaction of superconductivity and magnetism—two cornerstone phenomena of solid-state physics that at first sight are antitheses, but that on closer inspection provide a rich and nuanced tapestry of interrelated effects.
From superconductors possessing an intrinsic magnetic moment, to the artificial incorporation of magnetic material into a superconductor with the aim of improving its performance, his investigations cover the range from fundamental physics to applied materials science.
His interests also encompass these two fields individually, with important contributions in the development of practical superconducting technologies for application, particularly in the growing energy sector, and of hard magnetic thin films for data storage applications.
Stuart’s interest and expertise in thin film deposition spans the range of available techniques from basic thermal evaporation to advanced pulsed laser deposition.
He also has extensive experience of the solution deposition methods applicable in particular to superconducting coated conductors.
He applies these techniques to complex multinary systems with a particular interest in the epitaxial growth of materials that may be unavailable in bulk single crystal form, or where the dimensions available from an epitaxial thin film may enable experiments that are impossible on the limited single crystal sizes available.
Extending this interest, he is also keen to investigate metastable phases that may only be accessible in thin film form, whether stabilised through epitaxial strain or through non-equilibrium film growth processes.
Building on his thin film expertise, Stuart has a strong interest in the broader field of nanotechnology, with experience in cleanroom processing and device fabrication, photolithography, dry and chemical etching. He is also interested in the combination of traditional top-down nanotechnological processing with novel bottom-up approaches such as anodic alumina templating in order to achieve industrially relevant outcomes amenable to industrial scale-up and application.
Nature offers imaginative solutions to many of the problems faced in the development of advanced materials, not least complex processing capability in restricted-energy, environmentally-benign ambient conditions.
Several of these have garnered widespread attention, but many others exist to guide us to new methods of processing advanced materials. Stuart applies a range of bio-inspired techniques to the synthesis of highly synthetic materials, deriving indirect control over the detailed microstructure or relaxed processing conditions through the incorporation of bio-derived sacrificial additives to the synthesis protocol that affect the stages of the reaction process in complex ways, leading to a product that would be hard to obtain by conventional techniques. This field is at an early stage of development and a lot of the work is exploratory in nature, but holds immense promise for new capabilities.