The angular dependence of magnetization reversal in coupled elongated Ni80Fe20 nanorings

Abstract

We have investigated the effects of the magnetostatic interaction and anisotropy of elongated Ni80Fe20 nanoring arrays with various edge-to-edge spacing (s) using the focused magneto-optical Kerr effects measurements. The magnetic reversal behavior is markedly modified by varying s due to the magnetostatic interaction between neighbor rings. We also observed that the reversal process is very sensitive to the orientation of the magnetic field relative to the easy axis. For s 250 nm, a significant two-step switching corresponding to onion-to-vortex and vortex-to-reverse onion state transitions was observed as the magnetic field orientation (θ) is varied relative to the easy axis, and gradually disappeared until θ 90 ° (corresponding to the hard axis). Our experimental results are in a good agreement with micromagnetic simulations. © 2013 AIP Publishing LLC.