Magnetic nitrides

Nitrogen enters 3d metals and 3d-4f intermetallic compounds as an interstit ial provoking a dilation of the lattice. Iron-based alloys are most suscept ible to modification by nitrogen, which can turn them from weak to strong f erromagnets. In the 3d-4f compounds it is a major contributor to the crysta l held. The influence of nitrogen in BCC, FCC and HCP iron, and then in iro n-based intermetallics with 2 : 17, 1 : 12 and 3 : 29 structure types is re viewed. Important issues are the role of nitrogen in enhancing the iron mom ent and raising the Curie temperature. Progress in processing nitrogen-cont aining compounds is outlined, and applications of iron nitrides as permanen t magnets and as materials for use in magnetic recording are discussed. (C) 1999 Elsevier Science B.V. All rights reserved.