Computation of Magnetic Nano-Wave Structures

The recent discovery of the spin torque effect in nano-scale magnetic systems has enabled the application of localized destabilizing torques that can lead to time-periodic states that have been observed experimentally. A discussion of how to efficiently model and compute the effect of the spin torque in a nanocontact magnetic system will be discussed. Difficulties include non-locality, radiation of spin waves, strong nonlinearity, and time step restrictions. By use of a scaled polar coordinate grid and asymptotics of the thin film limit, it is demonstrated that spin torque can lead to novel time-periodic magnetic wave states such as spiral waves, localized modes, and a directionally controllable collimated beam of spin waves.