Magnetic Behavior of the Arrays of Iron Cylindrical Nanostructures: Atomistic Spin Model Simulations

Cylindrical ferromagnetic nanowires are of particular interest in nanomaterials science due to various manufacturing methods and a wide range of applications in nanotechnology, with special attention given to those with diameters less than the single domain limit. In the current study, the simulations of magnetic properties of isolated iron nanowires with a diameter of 5 nm and various aspect ratios, as well as two types of arrays of such nanowires (with hexagonal and square arrangement), were performed using atomistic spin model. In the case of a single nanowire, change of coercive field for different applied field directions with aspect ratio was discussed. It was shown that the evolution of the magnetization reversal mechanism from coherent rotation to domain wall propagation appears with increasing length of single nanowire. For the arrays of cylindrical nanostructures, it was revealed that different number of nearest neighbors for each nanostructure in square and hexagonal arrays have an influence on their magnetostatic interactions, which are the most significant for shortest interwire distances. The corresponding spin configurations during the remagnetization process showed the appearance of intermediate magnetization states (when a part of wires is magnetized parallel and part antiparallel to the field direction), connected with Barkhausen effect, which influence the observed hysteresis curves.