Maximum energy product of exchange-coupled Sm(FeCo)12/α-Fe nanocomposite particle

The effects of the coating surface orientation of the alpha-Fe soft magnetic layer on the Sm(Fe0.8Co0.2)(12) hard magnetic phase and the volume fraction of alpha-Fe, V-Fe, on the maximum energy product, (BH)(max) of exchange-coupled Sm(Fe0.8Co0.2)(12)/alpha-Fe nanocomposite magnet particles were micromagnetics OOMMF package was systematically investigated. The (BH)(max) of the reference model, Sm(Fe0.8Co0.2)(12) particles without Fe layer, was 630 kJ/m(3). In contrast, in the nanocomposite magnet particle model with soft magnetic layers on both sides of the hard magnetic phase, (BH)(max) reached a maximum value of 657 kJ/m(3) at V-Fe = 12% (Fe layer thickness, t(Fe) = 2 nm). In the model with alpha-Fe coating on the top and bottom surfaces of the hard magnetic phase, (BH)(max) = 636 kJ/m(3) at V-Fe = 4% (t(Fe) = 2 nm). Furthermore, the coating of the soft magnetic phase on both sides of the hard phase particles reduces the magnitude of the demagnetizing field, H-d of the nanocomposite magnet particles, indicating that the side coating of the soft magnetic phase is effective in increasing (BH)(max). These findings allow for a greater degree of freedom in the design of nanocomposite magnets by adjusting not only the V-Fe volume fraction of the hard/soft phases but also their arrangement.