A new type of nanocomposite magnets including elongated soft magnetic grains—computer simulation

Abstract Magnetic properties of nanocomposite magnets composed of α -Fe needles and aligned Nd 2 Fe 14 B grains were simulated based on the micromagnetic theory. The maximum energy product ( BH ) max vs. fraction of α -Fe curve had a peak, and the fraction corresponding to the peak depended on the size of α -Fe needles. For α -Fe needles with the size of 1.5 nm, the ( BH ) max value of approximately 800 kJ / m 3 was obtained at 80 vol% α -Fe. The obtained ( BH ) max value and the corresponding fraction of α -Fe were larger than those calculated for the magnet including cubic α -Fe grains, suggesting that the shape anisotropy suppresses the magnetization reversal in α -Fe needles in cooperation with the exchange coupling. Thus, a large ( BH ) max value are expected in the proposed nanocomposite magnets.