Article

Current-driven vortex domain wall dynamics by micromagnetic simulations

Department of Physics and Astronomy, University of Missouri, Columbia, Missouri, United States
Physical review. B, Condensed matter (Impact Factor: 3.66). 05/2006; 73(18). DOI: 10.1103/PhysRevB.73.184408
Source: arXiv

ABSTRACT Current-driven vortex wall dynamics is studied by means of a two-dimensional analytical model and micromagnetic simulation. By constructing a trial function for the vortex wall in the magnetic wire, we analytically solve for domain wall velocity and deformation in the presence of the current-induced spin torque. A critical current for the domain wall transformation from the vortex wall to the transverse wall is calculated. A comparison between the field- and current-driven wall dynamics is carried out. Micromagnetic simulations are performed to verify our analytical results.

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    • "The motion of domain walls (DWs) in magnetic nanowires is of strong fundamental and technological interest. Nanometresized magnetic structures can serve as ideal model systems for exploring the dynamics of DWs induced by external magnetic fields or spin-polarized currents [1] [2] [3] and offer the prospect of new spintronic devices for data storage or logic applications [4] [5]. "
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    • "Xiao , Zangwill and Stiles ( 2006 ) find that in the very narrow DW limit , the nonadiabatic torque oscillates across the DW , and extends over a length scale much larger than the DW width . Other authors find that the nonadiabaticity of the conduction electrons lead to the precession of their spins ( Waintal and Viret , 2004 ) , in turn generating spin waves which influence the DW motion ( Ohe and Kramer , 2006 ) . A recent study focused on GaMnAs also shows that the spin - orbit coupling increases the reflection of the carriers ( holes in this case ) at the DW , leading to spin accumulation and the enhancement of the nonadiabatic spin torque ( Nguyen , Skadsem and Brataas , 2007 ) . "
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    ABSTRACT: The current-induced motion of a domain wall in a semicircle nanowire with applied Zeeman field is investigated. Starting from a micromagnetic model we derive an analytical solution which characterizes the domain-wall motion as a harmonic oscillation. This solution relates the micromagnetic material parameters with the dynamical characteristics of a harmonic oscillator, i.e., domain-wall mass, resonance frequency, damping constant, and force acting on the wall. For wires with strong curvature the dipole moment of the wall as well as its geometry influence the eigenmodes of the oscillator. Based on these results we suggest experiments for the determination of material parameters which otherwise are difficult to access. Numerical calculations confirm our analytical solution and show its limitations.
    Physical Review B 09/2006; 75(5). DOI:10.1103/PhysRevB.75.054421 · 3.74 Impact Factor
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