Experimental SANS studies and micromagnetic simulations of neutron scattering on polycrystalline magnetic materials

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We intend to investigate the magnetic microstructure of multi-phase nanocomposites by combining magnetic-field dependent small-angle neutron scattering (SANS) measurements with full-scale micromagnetic simulations. Motivated by the recent observation of a novel angular anisotropy in the magnetic SANS cross section of the Fe-based two-phase alloy Nanoperm, we propose to develop a new micromagnetic method which will enable us to calculate the magnetization distribution and corresponding magnetic SANS cross section of a representative 3D nanocrystalline system. From an experimental point of view, the SANS experiments allow us to probe the spin microstructure in the sample volume and on a length scale of a few up to a few hundreds of nanometers. The computational part of the project will help us in identifying those parts of the nanocomposite parameter space where the most interesting physics is hidden. For this purpose simulations will be performed for various values of the external magnetic field (as SANS measurements) and for various microstructural and magnetic parameters of the composites (e.g., particle volume fraction, particle size, particle-size distribution, contrast in magnetization magnitude between the phases). The project will provide fundamental contributions to our basic understanding of magnetic neutron scattering from nanomagnets and improves our knowledge on the interplay between their nuclear microstructure and magnetic properties.