Magnetization of negative magnetic arrays: Elliptical holes on a square lattice

The magnetic properties of an array of elliptical holes in an Fe film have been investigated using the diffracted magneto-optical Kerr effect (D-MOKE), Lorentz scanning transmission electron microscopy (LSTEM), and Brillouin scattering. In the absence of a comprehensive theory for magnetization or magnons in these materials, we find that our results can be fit by a semiquantitative analysis treating the system as uniform, anisotropic film. D-MOKE clearly shows that magnetization reversal occurs with extensive domain formation when the field is applied along the short axis of the elliptical holes, and almost no domain formation when it is along the long axis, while LSTEM demonstrates that the domain location is controlled by the elliptical holes. A theory of D-MOKE, which enables a quantitative analysis of loops, is also presented.