1301.5963 (Shi-Zeng Lin et al.)

Driven skyrmions and dynamical transitions in chiral magnets    [PDF]

Shi-Zeng Lin, Charles Reichhardt, Cristian D. Batista, Avadh Saxena

We study the dynamics of skyrmions in chiral magnets in the presence of a spin polarized current. The motion of skyrmions in the ferromagnetic background excites spin waves and contributes to additional damping. At a large current, the spin wave spectrum becomes gapless and skyrmions are created dynamically from the ferromagnetic state, resulting in a liquid-like state of skyrmions. At an even higher current, these skyrmions are strongly deformed due to the damping and become unstable at a threshold current, leading to a paramagnetic-like state. We show how skyrmions can be created by increasing the current in the magnetic spiral state. We then construct a dynamic phase diagram for a chiral magnet with a spin polarized current. The instability transitions between different states can be observed as experimentally clear signatures in the transport measurements, such as jumps and hysteresis.

View original: http://arxiv.org/abs/1301.5963