Nanocrystalline Materials

The new profile of modern hard magnetic materials is supported by the recent conjunction of the nanocrystalline state responsible for the extrinsic magnetic properties with on the one hand the existence of the two families of intermetallic compounds possessing the three intrinsic magnetic characteristics required for high performance magnets (strong uniaxial magnetocrystalline anisotropy, elevated Curie temperature, and important magnetic moment) and on the other hand the opportunities of adapting the global magnetic characteristics to the profile of specific demands. The new generation of those remarkable alloys covers rare-earths (R = Nd, Pr, Sm) and 3d transition metals (T = Fe, Co) alloys for the former and 3d transition metal (Fe, Co) with 4d (Pd) and 5d (Pt) transition metals for the latter. Besides the use of these alloys in many components of electromechanical and electronic devices, their high anisotropy values made these compounds prominent candidates for ultra high density recording applications due to the feasibility of smaller grains still magnetically thermally stable.