Magnetic Properties of Interstitial Compounds Sm(Fe11Ti)X1-∂ (X=N,C)

New interstitial compounds Sm(Fe
11
Ti)X
1-∂
(X=N, ∂=0.8 and X=C, ∂=0.7) were prepared by heating a fine powder of Sm(Fe
11
Ti) in nitrogen and butane, respectively. The nitride showed a 3% increase in unit cell volume, an approximately 10% increase in iron moment (estimated from
⁵⁷
Fe Mössbauer spectra) and a 185K increase in the Curie temperature to 769K. The uniaxial anisotropy is destroyed, however, and A
20
≫≫10Ka
0
^-2
in the nitride. These effects are compared with those in R
2
Fe
17
nitrides and carbides, and the differences are explained qualitatively in terms of Coehoorn's model taking into account the configuration of interstitial atoms around the rare earth atoms.