NEW MAGNETS FROM INTERSTITIAL INTERMETALLICS

The outlook for improving the energy product of permanent magnets beyond the theoretical limit of 516kJ/m(3) for Nd2Fe14B is discussed. Most promising are nanostructured two-phase magnets consisting of an aligned hard-magnetic skeleton phase possessing exceptionally high uniaxial anisotropy and a soft-magnetic phase which assures a high magnetization. Brown's paradox is discussed for inhomogeneous magnets, and micromagnetic calculations are used to predict energy products as high as 1090kJ/m(3) in suitable nanostructured Sm2Fe17N3/Fe65Co35 composites, such as multilayers or disordered two-phase magnets with common c axis.