Maximum energy product of isotropic Nd-Fe-B-based nanocomposite magnets

The maximum energy products, (BH)max, of isotropic Nd-Fe-B-based nanocomposite magnets were calculated by a three dimensional model (10×10×10) that incorporated non-uniform magnetization reversals by subdivisions of the grains. Based on the results of our simulation, the largest obtainable (BH)max for a sample with 60% soft and 40% hard grains is about 290 kJ/m3. This value is lower than the previous crude estimate of 400 kJ/m3 but is almost twice as large as the experimental measured maximum of 160 kJ/m3 suggesting that further improvement in (BH)max is possible if the nanostructure of an actual magnet can made close to the theoretically ideal structure.