21st October 2009 1 p.m. 54/10B
Mathematical Aspects of Micromagnetism
Dr Thomas Fischbacher
University of Southampton
- Categories
- Materials, Micromagnetics
- Submitter
- Hans Fangohr
Experience tells us that, while all materials react to magnetic fields, some show a curious phenomenon called "ferromagnetism", producing nonzero magnetization all on their own, even without any applied field. Starting from just this observation, a simple thought experiment shows that, as we go to small length scales, magnetism at some point must start to must behave very differently from how we experience it when playing with macroscopic magnets. The study of these "first corrections to macroscopic magnetism at short length scales", actually needed for consistency, but interesting in their own right, is called "micromagnetism", and has applications from sensors to data storage systems.
In this talk, I want to (a) give a gentle introduction to fundamental aspects of the physics of magnetism, (b) introduce the micromagnetic model, (c) briefly discuss both static aspects - i.e. magnetisation structures of minimal energy, as well as magnetization dynamics, (d) explain some of the mathematical challenges in micromagnetic simulations, and (e) finally show a curious theorem, including its proof, that magnetism cannot exist.