ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Iron-rich rare-earth (R) compounds, such as R2Fe17 do not show great potential for high-performance magnet materials due primarily to their low Curie temperatures (Tc∼300–400 K). However, relatively large quantities of nitrogen or carbon atoms can be introduced into the structure, resulting in a dramatic enhancement of magnetic properties including Tc (≥700 K). The N or C atoms cause a volume expansion of a few percent of the unit cell without changing the crystal structure. The large increase in Tc can be attributed to the volume dependence of the Fe–Fe exchange interactions. A large uniaxial anisotropy field develops for R=Sm upon nitriding/carbiding with an anisotropy field that is almost double the value for Nd2Fe14B at room temperature. Problems including the precipitation of soft magnetic phases (mainly α–Fe) and the limited thermal stability of the nitrides have so far restricted the applications of these compounds. Here data are presented on combined carbide/nitride alloys prepared using a novel technique. These alloys exhibit many of the advantages of the pure compounds but with greater thermal stability and less interference from precipitated phases. A typical material, Sm2Fe17(NxC1−x)3−δ has a Tc of 758 K and an anisotropy field (μ0HA) of 15 T at room temperature.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.353456
