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

Magnetic properties of nanocomposite magnets composed of alpha-Fe needles and aligned Nd2Fe14B grains were simulated based on the micromagnetic theory. The maximum energy product (BH)(max) vs. fraction of alpha-Fe curve had a peak, and the fraction corresponding to the peak depended on the size of alpha-Fe needles. For alpha-Fe needles with the size of 1.5 nm, the (BH)(max) value of approximately 800 kJ/m(3) was obtained at 80 vol% alpha-Fe. The obtained (BH)(max) value and the corresponding fraction of alpha-Fe were larger than those calculated for the magnet including cubic alpha-Fe grains, suggesting that the shape anisotropy suppresses the magnetization reversal in alpha-Fe needles in cooperation with the exchange coupling. Thus, a large (BH)(max) value are expected in the proposed nanocomposite magnets. (c) 2006 Elsevier B.V. All rights reserved.