Studies of new rare-earth permanent magnets

Research on permanent magnet materials since the late 1980s at the University of Manitoba is described in the context of contemporary research elsewhere. The general objectives sought for a material to be useful as a permanent magnet are identified, The research includes atomic substitutions of the super permanent magnet Nd2Fe14B, other potentially useful ternary crystal structures, interstitial solution of carbon or nitrogen atoms and composite materials, Although x-ray diffraction, magnetization and other measurements have been made over a range of temperatures, the use of Mossbauer spectroscopy has been emphasised. For example, the determination of the site occupancy by various substituted atoms has let to an atomic pair model that quantitatively describes the Curie temperatures. Recently, it has been discovered that silicon stabilizes the 2-17 structure and permits gas-phase reactions at temperatures of over 700 degrees C. Composite materials are discussed in terms of some proposed models.