Nanocrystalline iron based-alloys

The magnetic properties of nanocrystalline Sm2Fe17-xSixC2 alloys were studied in the temperature range 4.2-800 K and fields up to 10 T. The saturation magnetizations are little higher than in noncarbonated systems having the same composition. The Gamma = dInT(c)/dlnv values show linear dependences on the Curie temperature, T-c, suggesting that iron moments are mainly localized. The gamma=dlnJ(eff)/dlnv=16.4, a value close to that determined in highly carbonated R2Fe17Cx polycrystalline compounds where R is a rare-earth or yttrium. Band structure calculations show linear dependences of Fe moments, as well as of R5d band polarizations on De Gennes factor. The magnetic properties of NdeFe88-xMxB6 nanocomposites with M=V or Fe were also studied. Remanent inductions B-r = (0.62-0.67) were obtained.