Title:Domain wall motion and spin wave

Speaker: Prof. X. R. Wang (The Hong Kong University of Science and Technology)

Time:14:30pm, Sept. 12, 2012

Venue:Salon Room, Institute of Semiconductors, CAS

Abstract: In this talk, I will discuss the interplay between magnetic domain wall (DW) motion and spin waves (SW). Both DW and SW are the fundamental excitations of magnetic systems. In a magnetic nanowire, we show that DW propagation accompanies normally spin wave emission on the one hand. On the other hand, a SW passing through a DW tends to drive the DW moving against the SW propagating direction. This interplay between DW and SW leads to very rich physics. Following recent discovery will be presented: 1) Magnon, quanta of SW, can efficiently mediate spin angular momentum transfer between SW and DW because magnons are spin-1 particles.2) Magnonic spin-transfer torque can drive a DW to propagate at a high speed. 3) DW motion will generate SW, and, as a result, a static magnetic field can even drive a DW to propagate along a dissipationless nanowire through SW emission. 4) The widely believed Walker rigid-body propagation mode is not stable in a dissipated wire because of the SW emission, and DW propagation is locked into a soliton mode. Furthermore, our studies imply that two DWs can interact with other through the SWs.