Research

 

Micromagnetic simulation

Permanent magnets

Reversal

Reversal processes of single Nd-Fe-B grains of a permanent magnet, with and without a soft surface defect. >>Paper<<

Visualizations of the computed magnet\-ization data during reversal of soft prolate spheroids for aspect ratios (a) 1.95 and (b) 15.6, showing the different reversal modes.

Numerical simulations of the reversal  of Co spheroids, soft magnetic nanoparticles that could be used to construct a new type of shape anisotropy based permanent magnet. >>Paper<<

  • Permanent magnets play a crucial role in many modern technologies, particularly in motors and electrical generators. These are used in electric vehicles, wind turbines, marine propulsion, manufacturing and so on.
  • Our work focuses on improving the performance of permanent magnets so that they can be made more cheaply and provide higher levels of operational efficiency and output. We do this by finding new magnetic materials and new ways of combining materials in nanostructured permanent magnets.

Domain wall memory

  • Magnetic random access memory (MRAM) is a high performance computer memory that stores data using the magnetization of soft magnetic elements, instead of electric charge, which is how transistor memories works in current computer technologies. It is also non-volatile, so the current state is stored even when the device is powered off.
  • The current limitations to MRAM include the fact that it cannot currently compete with the storage density of flash memory, which is a more mature technology and, crucially, very profitable, and there is only one MRAM chip so far available on the market.
  • Domain wall MRAM (DW-MRAM) may provide a type of memory where the power consumption is lower and where the reversal mechanism and switching field of voltage are more consistent, giving less errors in operation.

Magnetic spin waves

  • Ferromagnetic spin waves are a way to transmit data through a thin film or along a nanowire. Many believe that they could be the building blocks of future computer architectures. This is now a very active field of research.
Ferromagnetic spin waves traversing a bend in a NiFe nanowire.

Ferromagnetic spin waves traversing a bend in a NiFe nanowire.

Optimization

Optimization applied to structural mechanics

  • Coupling finite element simulation codes with optimization algorithms allows one to find optimized solutions to many problems. In our work this has been applied to the optimization of structural wood joints, hard disk drives and permanent magnets.
Robust surface response optimization algorithm applied to a design problem to minimise wood joint stress.

Robust surface response optimization algorithm applied to a design problem to minimize wood joint stress.

System Dynamics

  • Real systems can often be broken down into constituent components but can quickly exhibit complex behaviour that are hard to understand by traditional methods. System Dynamics provides a way to model and test such systems. Our work focusses on power station planning and operations, specifically on matching load and demand in power grids where renewable energy sources are being incorporated, in order to suggest optimal levels of each type of generation. Connection to national and international electricity markets is included.
Fig. 1

Model of power generation grid including naive load model, coal, solar, wind and hydroelectric power sources. Various scenarios can be tested.

Fig. 2

Hydroelectric power station operation during a single 24h cycle.

Lab-on-chip cancer diagnostics

  • Cancer cell detection and filtering
    • Circulating tumour cells (CTCs) flow through the blood and can metastasise to form new cancers in other parts of the body. Detection and diagnosis are critical to saving lives. Lab-on-chip methods are being developed to count and filter CTCs cheaply and effectively.