CRYSTAL-FIELD IN NITROGENATED RARE-EARTH INTERMETALLICS

The crystal-field in Sm2Fe17N3-delta and Sm(Fe11Ti)N1-delta due to interstitial nitrogen has been investigated. Intrinsic parametrization in the superposition model allows separation of the crystal field created by a neighboring nitrogen atom from a purely geometrical factor, which is different for Sm2Fe17N3-delta and Sm (Fe11Ti)N1-delta. Using published magnetic data, values for the intrinsic parameter A2 per nitrogen atom of A2=200+/-60 Ka0(-2) and A2=270+/-60 Ka0(-2) for Sm2Fe17N3-delta and Sm(Fe11Ti)N1-delta, respectively, are obtained. Because of charge penetration, which is discussed in the form of an explicit crystal-field weight function, it is not possible to interpret A2(0) or A2 as crystal-field parameters independent of the 4f ion.