Graphene Hall-effect nanosensors to optimise high current superconducting tapes for applications in 'smart' power grids

Rapid population growth and societal developments are placing increasing stress on the environment and have led to intensified demands for the realisation of new technologies. A pressing example is the threat from climate change. While this issue can in part be tackled by adopting renewable energy sources (e.g. offshore windfarms), these are often remote with heavy losses in energy during transmission. This problem can be addressed by implementing 2nd generation high temperature superconducting (2G-HTS) tapes for power transmission. However, maximising the current-carrying capacity of these requires optimisation of defect densities for the pinning of magnetic vortices without degrading the critical temperature below which the tapes operate.

More often than not, advances in such technologies have emerged alongside the development of superior measurement and sensing instrumentation. Working with partners Nanomagnetic Instruments Ltd, this project seeks to exploit the benefits of the novel materials, graphene and h-BN, to produce advanced Hall sensors to be incorporated in scanning probe microscopes. These can be used to accurately map magnetic fields and characterise current flows around microscopic material defects with resolution down to the nanoscale. The encapsulation of graphene in h-BN boosts the sensor’s capabilities by greatly increasing the carrier mobility and reducing unwanted 1/f noise for maximum signal-to-noise ratios. In the course of this project, these new scanning Hall probes will be exploited to drive forward the optimisation of the aforementioned 2G-HTS tapes, working together with tape manufacturers from China (Shanghai Superconductor) and the USA (AMSC).

Additionally, the project aims to develop sensors for susceptometry by integrating them with microscopic magnetic field coils. These can be implemented in the process control of additive manufacturing systems, for instance, to map defects in manufactured samples. We will work with partners Renishaw, who are interested in monitoring their metal powder bed fusion technologies. The same approach can also be used in other industries/sectors, for example in the routine characterisation of ferromagnetic data storage media.


David Collomb
David Collomb

David obtained a 1st class MSc degree from the University of Nottingham, taking modules specialising in nanoscience and low dimensional physics. As masters project, David spent four months on exchange to Fudan University in China working on a novel optical cold-atom imaging method exploiting currently perceived drawbacks from atom-microchips and nano-patterned lenses. He has additionally gained experience in AFM installation, calibration and operation during an Ogden Trust funded placement at Royal Holloway University of London. David's main interest and childlike fascination is in nanoscience. He is especially excited about; nano-scale instrumentation, fabrication, physics of nanoscale materials and applications of nanoscale devices to solve not just modern physics problems, but also in cross-disciplinary fields. Alongside this, David has secondary education teaching and public outreach experience through the Ogden Trust and the University of Nottingham, as well as additional studies abroad in South Korea.

Simon Bending
Simon Bending

Prof. Simon Bending obtained a BA Hons degree (1st class) in Natural Sciences-Physics from the University of Cambridge in 1979, and a PhD in Applied Physics from Stanford University in 1985 under the supervision of Prof Mac Beasley. Following post-doc positions with Dr Pierre Guéret at IBM Zurich and Prof. Klaus von Klitzing at the Max Planck Institut für Festkörperphysik he was appointed as a Physics Lecturer at the University of Bath in 1989. After a series of promotions he became a Professor in 2000 and since 2013 has been Head of the Department of Physics. He has published nearly 200 papers on superconductivity, nanomagnetism and scanning probe microscopy, much of this work evolving from the development of Hall-effect nanomagnetometry and scanning Hall probe microscopy. Highlights of his research include studies of vortex matter in highly anisotropic superconductors, ferromagnet-superconductor hybrids, domain wall phenomena in ferromagnetic thin films and two-dimensional superconductors & graphene. His work has been recognised by several awards including the Philip Morris (Germany) Research Prize for Information and Communication (1990), a Leverhulme Trust Senior Research Fellowship (1999/00) and the IOP Mott Prize Lecture at the joint European Physical Society meeting (2002). SJB is co-director of the Exeter/Bath Centre for Graphene Science (EPSRC/HEFCE, £5M) and deputy director of the £4.1M Bath/Bristol Centre for Doctoral Training in Condensed Matter Physics. He also represents the UK on the management committee of the EU NanoSC Cost Action Nanoscale Superconductivity, a network linking researchers in this area in 20 European countries, and was Chair of the Institute of Physics Superconductivity Group from 2011-2016.

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