Edge defects inducing asymmetric transverse domain walls created in Ni80Fe20 nanowires

Abstract

Abstract Polycrystalline permalloy nanowires (NWs) with different widths were studied by means of a Lorentz microscope associated with micro-magnetic simulations. Each NW was designed to create a single head-to-head transverse domain wall (DW). Edge defects at the long edges of those NWs were incrementally controlled. Therein, a single pixel at different positions along the NW edges was removed. The horizontal NWs were rotated with different angles, i.e. ±5°, ±10°, ±30° and ±45°, to produce a certain level of edge roughness. Some curved NWs with different widths were also designed, simulated and patterned. Lorentz images of those curved NWs were recorded. The asymmetric levels of such created walls were measured and correlated to our wall phase diagram. The obtained results showed that the edge defects created along either side of a NW strongly induce the asymmetric level of a transverse DW.