Micromagnetic modeling and small-angle neutron scattering characterization of magnetic nanocomposites

A new methodology for micromagnetic simulations of magnetic nanocomposites is presented. The methodology is especially suitable for simulations of two-phase composites consisting of magnetically hard inclusions in a soft magnetic matrix phase. The proposed technique allows us to avoid unnecessary discretization of the ``hard'' inclusions (these are normally in a single-domain state) but enables arbitrary fine discretization of the ``soft'' phase. The method is applied to the determination of the equilibrium magnetization state of an iron-based nanocomposite from the Nanoperm (FeZrBCu) family of alloys and to the calculation of the corresponding small-angle neutron scattering (SANS) cross-section. The results of our simulations exhibit a remarkable agreement with nontrivial ``clover-leaf'' SANS cross-sections observed experimentally.