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New Paper on Ultrafast Switching in Ferrimagnets

Yesterday saw a long awaited paper into the mechanism behind heat induced switching in ferrimagnetic materials. Using the newly developed Landau-Lifshitz-Bloch equation for a ferrimagnet we linearize the equations of motion in the conditions seen in heat induced switching, arriving at a set of dynamical equations. These dynamical equations show that the reversal path occurs via a transfer of angular momentum from the linear motion to the transverse motion. We support these analytics by making comparisons with atomistic spin dynamics.

Spinwaves Symposium 2013, St. Petersburg, Russia

Last week saw the 2013 spinwaves symposium held in St. Petersburg and hosted by the Ioffe Physical-Technical Institute of the Russian Academy of Sciences. A combination of invited and contributed talks made for a very interesting meeting demonstrating the latest advances in magnetism. I presented a talk looking at spin-spin correlations during ultrafast demagnetisation processes.

Spin Waves 2013

St. Petersburg is a very impressive city and gave a good impression on my first visit to the country. I look forward to returning to Russia, perhaps for spinwaves 2015 (hopefully next time I won’t leave my car keys in my hotel room!).

New Paper on Relaxation Processes in Rare-Earth doped Permalloy

On the 19th November this month Matt Ellis, a colleague at York, finally had his paper on Rare-Earth doped Permalloy published in Physical Review B. This latest paper uses a localized Heisenberg model, combined with the Landau-Lifshitz-Gilbert equation of motion for atomic magnetic moments, to study the effects of doping of different rare-earth metals on the magnetization dynamics of Permalloy. The model allows one to study the effect of different energy transfer channels to and from the spin system.

This systematic study looks at the effects of doping on properties such as, the longitudinal relaxation after femtosecond heating, and the transverse relaxation time after exciting the system away from it’s anisotropy axis.