Ballistic Current induced Effective Force on Magnetic Domain Wall

C Wang,K Xia

doi:10.5101/nml.v1i1.p34-39

Abstract

The collective dynamics of magnetic domain wall under electric current is studied in the form of spin transfer torque (STT). The out-of-plane STT induced effective force is obtained based on the Landau-Lifshitz-Gilbert (LLG) equation including microscopic STT terms. The relation between microscopic calculations and collective description of the domain wall motion is established. With our numerical calculations based on tight binding free electron model, we find that the non adiabatic out-of-plane torque components have considerable non-local properties. It turns out that the calculated effective forces decay significantly with increasing domain wall widths.

Highlights

The application of spintronics [1] requires effective ways of spin manipulations in nanoscale devices
Electric currents can be spin-polarized by passing through magnetic domains, and the polarized spins of the conducting electrons can exert spin transfer torque (STT) to the localized magnetizations when going through a magnetic domain wall
They found that the domain walls (DWs) motion will be dominated by the effective force on the DW, which is rooted from the reflection of the electrons incident on the DW

Summary

Ballistic current induced effective force on magnetic domain wall

The collective dynamics of magnetic domain wall under electric current is studied in the form of spin transfer torque (STT). The out-of-plane STT induced effective force is obtained based on the Landau-Lifshitz-Gilbert (LLG) equation including microscopic STT terms. Electric currents can be spin-polarized by passing through magnetic domains, and the polarized spins of the conducting electrons can exert spin transfer torque (STT) to the localized magnetizations when going through a magnetic domain wall. The dynamics of magnetic domain walls (DWs) in the presence of electric current are still not well understood, especially for the components of spin transfer torques perpendicular to the plane where the local magnetization’s directions change. The current-driven domain wall dynamics is studied based on the Landau-Lifshitz-Gilbert equation, the connection between effective force and out-of-plane STT on each site is obtained.

We assume that the magnitude of the magnetization will

2SMs cos

NwS F d OSL

NUMERICAL CALCULATION AND DISCUSSION

CONCLUSION