MOSSBAUER-SPECTRA AND MAGNETIC-PROPERTIES OF SM2(CO, FE)17 ALLOYS

Sm2(Co1-xFex)17 alloys form the basis of a new class of permanent magnets. We have investigated these materials with Fe-57 Mossbauer spectroscopy. Alloys with x less-than-or-equal-to 0.5 have easy-axis anisotropy at room temperature; their spectra can be fitted with sextets corresponding to the four nonequivalent sites of the Th2Zn17 structure. Fe hyperfine fields increase with increasing Fe concentration. An average Fe moment of almost-equal-to 2.0-mu(B) is estimated. Fe atoms show a strong preference for occupying the 2c dumbbell sites. This preference is reduced in Zr-containing alloys used for magnet preparation.