Analysis of temperature-dependent magnetization in Sm-Fe-C compounds using a two-sublattice model

The temperature dependence of magnetization in Sm/sub 3/Fe/sub 20/C/sub x/ (x =0.3, 0.6, 0.8) and Sm/sub 2/Fe/sub 16.5/C/sub 1.0/ intermetallic compounds with rhombohedral structure has been analyzed using molecular field theory. On the basis of a two-sublattice model, the molecular field coefficients are calculated using a numerical fitting method. The Curie temperature and the Fe-Fe, Sm-Fe, Sm-Sm magnetic interaction energies for the compounds are determined from these coefficients. The results show that the increase of the Curie temperature (T/sub c/) with the increase of carbon content x is attributed mainly to the enhancement of the Fe-Fe exchange interaction energy caused by carbon atoms added.<
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