Spin-wave resonance reflection and spin-wave induced domain wall displacement

Abstract

Spin-wave propagation and spin-wave induced domain wall motion in nanostrips with a Néel wall are studied by micromagnetic simulations. It is found that the reflection of spin waves by the wall can be resonantly excited due to the interaction between spin waves and domain-wall normal modes. With the decrease of the saturation magnetization Ms (and the consequent increase of the wall width), the reflection is diminished and complete transmission can occur. The domain wall motion induced by spin waves is closely related to the spin-wave reflectivity of the wall, and may exhibit different types of behavior. The reflected spin waves (or magnons) give rise to a magnonic linear momentum-transfer torque, which drives the wall to move along the spin wave propagation direction. The maximal velocity of the domain wall motion corresponds to the resonance reflection of the spin waves. The transmitted spin waves (or magnons) lead to a magnonic spin-transfer torque, which drags the wall to move backwardly. The complicated domain wall motion can be described qualitatively by a one-dimensional model incorporating both the magnonic linear momentum-transfer torque and the magnonic spin-transfer torque. The results obtained here may find use in designing magnonic nanodevices.

Quantifying arbitrary-spin-wave-driven domain wall motion, the creep nature of domain wall and the mechanism for domain wall advances

“…It is worthwhile to mention that, by observation of this study, we also find accordance between the averaged velocity of DW and reflection with respect to peak positions, which exhibits consistency to studies that report strong reflection dependence of DWM and support LMTT [35,39,42]. However, as mentioned, the theory of LMTT should not be able to yield the required STT.…”

“…For these reasons, new possibilities are still being explored. Recent progress includes making use of voltage [21], temperature gradient [22][23][24][25][26][27][28], mechanical stress [29,30], laser pulses [31], spin waves (SWs) [32][33][34][35][36][37][38][39][40][41][42], etc.…”

“…STT and LMTT can only be partially correct due to the fact that SW transmission varies with frequency and the direction and velocity of DWM indeed depend on the SW transmission coefficient through DW [35,39,42]. Combining STT and LMTT [35,42] successfully achieved a qualitative agreement with simulation. However, the effort seemed to fail to reproduce the results on a more quantitative level.…”

“…That is, the linear momentum is changed by 2ÿk. The transfer of linear momentum to DW rewrites the effective field in LLG and causes forward motion of DW [35,42]. STT and LMTT can only be partially correct due to the fact that SW transmission varies with frequency and the direction and velocity of DWM indeed depend on the SW transmission coefficient through DW [35,39,42].…”

Equations of motion and frequency dependence of magnon-induced domain wall motion

“…Magnon-induced domain wall motion has recently been studied analytically, 1-4 numerically [5][6][7][8][9][10][11][12][13] and experimentally. 14,15 The numerical analyses have uncovered a wide range of domain wall behaviors.…”