Magnetisation reversal in epitaxial Fe(1 0 0) disks studied by high resolution scanning Hall probe microscopy

Magnetisation reversal has been investigated in 2 μm diameter epitaxial Fe(1 0 0) disks using scanning Hall probe microscopy. The high spatial resolution (∼200 nm) and non-invasiveness of our Hall sensors has allowed the domain structure, which is governed by biaxial in-plane anisotropy, to be resolved in the disks. We find that most disks appear to exhibit a double vortex magnetisation reversal mechanism, in agreement with the results of micromagnetic simulations with the OOMMF code. Although the switching dynamics tend to be influenced by domain wall pinning sites within our Fe samples, we find a strong correlation between most of our measured images and the results of simulations. Additional confirmation for the double vortex reversal mechanism is drawn from local measurements of out-of-plane magnetic induction loops.