Computer simulated magnetic properties of Nd2Fe14B/α-Fe nanocomposite magnets

Micromagnetic models of assemblies of randomly oriented, exchanged coupled nanocrystals consisting of magnetically hard Nd2Fe14B and very soft alpha Fe have been simulated. The modeling of two-dimensional chessboard consisted of 50 vol. % hard and 50 vol. % soft nanocrystals with the size varying from 5, 10, 25, to 50 nm. Hysteresis curves of each model system were obtained by solving the Landau-Lifshitz-Gilbert equation by time integration of the stiff differential equations. The simulation was focused on the effect of domain size and distribution in each nano crystal of fixed size. Eventually the simulated results were compared with magnetic properties obtained from experimental results of NdFeNbB based magnetic alloys showing the identical grain sizes to the simulated model. The present study exhibited the important role of soft phase in terms of volume fraction and arrangement of the phase.