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.

Ahmet Oral
Ahmet Oral

Prof. Ahmet Oral was born in 1965 and obtained his B.S. degree in Electronics in 1987 from METU and PhD in Physics from Bilkent University, Ankara, Turkey in 1994. He has built the first Scanning Tunnelling Microscope(STM) in Turkey in 1989 during his MSc. thesis. He has also built the first UHV-STM in Turkey, during his PhD thesis. Dr. Oral spent 5.5 years in Bath and Oxford as post-doc, working on Scanning Hall Probe & Atomic Force Microscopes, before returning to Bilkent in 1999 as a faculty member. He is recipient of M. Parlar Young Scientist Award in 1993, Violette and Samuel Glasstone Research Fellowship in Science in 1998 and TÜBİTAK Young Scientist Award in 2002. He worked at Bilkent as Assistant, Associate and full professor between 1999-2008. He was a full professor at Sabanci University between February 2008 and April 2013. He was elected Associate Member of Turkish Academy of Sciences(TÜBA) in 2001 and Full Member in 2009. He resigned in 2011 from TÜBA. He is one of the founding members of The Academy of Science, İstanbul, Turkey in 2011. Dr. Oral is also the founder of NanoMagnetics Instruments Ltd. Oxford, U.K., NanoManyetik Bilimsel Cihazlar and NanoSis in Ankara, Turkey and NanoMagnetics Instruments USA, Manufacturing Scanning Hall Probe Microscopes, micro and nano-Hall sensors, Atomic Force Microscopes, Magnetic Force Microscopes & Scanning Probe Microscopes at a wide temperature range (10mK-300K). He has 60 technical publications in ISI cited journals and two book chapters. He has been a Professor in at the Physics Department in Middle East Technical University (METU) since April 2013.

Project at other locations