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Nanomagnetic particles can have properties and useful functionality that is quite different from the same materials in the bulk. Chemical synthesis can be used to control the size, shape and dispersity of nanoparticles, while modification of the surface can greatly modify their magnetic properties. Surface functionalisation can also be used to induce self-organisation or to refine the nanoparticle properties for different applications. Such particles have a range of potential applications, ranging from magnetic storage and sensors through to biological assays and directed drug delivery.

In addition to the work we have undertaken on nanomagnetic materials specifically intended for application in magnetic recording media, we are also currently involved with a number of groups in the UK, Japan, Korea and France to explore the fabrication, properties and applications of nanoparticles produced via nanocolloidal synthesis. These routes can lead to particles with very narrow size distributions and a well defined particle separation in the as-deposited state. Particle diameters as small as 2 nm can be produced with a size dispersion of only 5%.

We are also working with the group of Professor Laura Heydermann at the ETH, Zurich to explore the collective properties of interacting arrays of artificially arranged and controlled nanoparticles produced using electon beam lithography. An example of this is our recent exploration of spin ice physics using artificial nanomagnetic arrays.

Artificial array of nanomagnetic island in a Kagome spin-ice configuration. The fluctuating and interacting dipoles exhibit the phase transitions shown schematically on the right ().

Selected Publications

Agglomeration and sintering in annelaed FePt nanoparticle assemblies studied by small angle neutron scattering and X-ray diffraction.
Thomson, T. and Lee, S.L.,
PRB 72 (6): Art. No. 064441, 2005.