Control of micromagnetics in Permalloy nanomagnets by means of indentation

The competition of exchange and magnetostatic interaction in nanomagnets is known to lead to the formation of configurational anisotropy. We present an effective method of controlling the configurational anisotropy and underlying micromagnetic configurations in isotropic Permalloy square prisms by edge indentation. Finite difference micromagnetic modeling of such indented square prisms gives five ground state micromagnetic configurations, the relative energies of which are determined by the structure size and depth of indentation. A micromagnetic phase diagram for the system is constructed on a size-indentation plane and is confirmed by direct magneto-optical measurements on nanofabricated Permalloy structures. The effect of indentation is to suppress curling micromagnetic configurations resulting in single domain behavior in indented structures as large as 400 nm.