Spatially ordered arrays of magnetic nanowires: Polarized-neutron scattering investigation

The structure and magnetic properties of magnetically ordered arrays of magnetic nanowires formed on the basis of porous aluminum oxide films have been investigated by the small-angle polarized-neutron scattering method. Small-angle scattering intensity patterns exhibit several diffraction maxima (up to the third reflection order), which correspond to scattering from the highly ordered porous structure of the matrix and on the hexagonal packing of magnetic nanowires. The observed reflections are imposed on noticeable diffuse scattering associated with the defects of the structure. A theoretical solution is obtained for describing neutron diffraction in the dynamical limit on the superstructure of magnetic nanowires incorporated into the diamagnetic matrix. Several contributions to scattering that have been analyzed are the nonmagnetic (nuclear) contribution, the magnetic contribution depending on a magnetic field, and the nuclear-magnetic interference indicating the correlation between the magnetic and nuclear structures. A detailed pattern of the remagnetization of an ordered array of the magnetic nanowires has been obtained and it has been shown that polarized neutron scattering provides information inaccessible by the standard magnetometric methods.