Stochasticity of domain wall pinning in curved ferromagnetic nanowires investigated by high-resolution Kerr microscopy

The stochasticity of magnetic domain wall positioning after applying rotating magnetic fields to polygonal ferromagnetic nanowire-type magnetic field sensor structures is investigated. High-resolution magneto-optical Kerr effect microscopy is utilized to determine the travelled domain wall distances. The impact of the applied magnetic field amplitude, of field orientation, and of the polygon angle on domain wall positioning is systematically investigated to identify conditions for a deterministic response. Under certain conditions of magnetic field angle and amplitude, a highly predictable behaviour of domain wall positions with standard deviations below 30 nm is achievable. The presented magneto-optical method enables high throughput detection of domain wall positions with nanometer resolution.