Measurements of nanoscale domain wall flexing in a ferromagnetic thin film

We use the anomalous Hall effect to probe the nanoscale behavior of a single magnetic domain wall (DW) in (Ga,Mn)As thin film devices with out-of-plane magnetic anisotropy. Video-rate magneto-optical Kerr microscopy is also used to confirm the variation of the AHE with DW position. Our all-electrical technique allows us to observe a low field flexing regime of DW motion, distinct from the stochastic creep regime that occurs at higher fields. This flexing regime is characterized by a larger DW mobility, linear response to applied field, and non-hysteretic motion which is repeatable within our $\sim 5$ nm experimental resolution. We then analyze the flexing and depinning behavior of the DW to estimate the density and strength of pinning sites. Supported by the ONR MURI program.