A study of tailored domain wall geometries in ferromagnetic nanowires using Lorentz microscopy

[摘要] This workpresentsresults on the degree of asymmetry in Transverse Domain Walls (TDWs) by means of micro-magnetic simulation and Lorentz microscopy. Here, head-to-head (H2H)-TDWs were simulated in straight permalloy(Py)-Ni80Fe20nanowires. This aimsto explore how to define symmetry and asymmetry of TDWs viaa quantitative measurement of symmetry/asymmetry as described bya correlation between magnetization components (Mx, My) and region areas (A1, A2) inside TDWs. Experimentally, curved nanowires ofdiffering widths were patterned by Focussed-Ion-Beam (FIB) irradiation. Lorentz microscopy experiments indicate that the degree of asymmetry of TDWs in the curved nanowires is strongly affected by structural effects, i.e.degree of edge roughness. Our results are a new route-map of quantitative measurement for transition between symmetric and asymmetric TDWs.The results are helpful for the determination ofTDW configurations inthe static state after the application of a magnetic field orelectrical current pulse when TDWs are driven by magnetic field or current.Indeed, our results may support a greater understanding of DW creation and propagation in magnetic nanowires which are of interest for concepts of high-density and ultrafast nonvolatile data storage devices such as racetrack memory and magnetic logic gates.

[发布机构] University:University of Glasgow;Department:School of Physics and Astronomy

[关键词] QC Physics