Effects of Cr substitution on the formation, structure and magnetic properties of Sm/sub 2/(Fe,Cr)/sub 17/C/sub x/ alloys

The effects of Cr substitution on the formation, structure and magnetic properties of Sm/sub 2/(Fe,Cr)/sub 17/C/sub x/ alloys have been systematically studied on arc-melted and melt-spun samples using XRD, TEM and magnetic measurements. It has been found that Cr substitution is an effective way to form the Sm/sub 2/(Fe,Cr)/sub 17/C/sub x/ carbides. The minimum amount of Cr needed to form an almost single 2:17 Sm/sub 2/Fe/sub 17-y/Cr/sub y/C/sub 2/ phase is around y=2 and the maximum amount of carbon for Sm/sub 2/Fe/sub 15/Cr/sub 2/C/sub x/ to remain in a single 2:17 structure is around x=2. Magnetic measurements reveal that the Cr substituted Sm/sub 2/(Fe,Cr)/sub 17/C/sub x/ carbides have a strong uniaxial magnetocrystalline anisotropy with anisotropy fields higher than 90 kOe obtained in both the Sm/sub 2/Fe/sub 15/Cr/sub 2/C/sub 2/ and Sm/sub 2/Fe/sub 14/Cr/sub 3/C/sub 2/ carbides. The highest coercivity of 13.2 kOe has been obtained in Sm/sub 2/Fe/sub 15/Cr/sub 2/C/sub 2/ melt-spun ribbons. However, both the Curie temperature and the magnetization are found to decrease with Cr substitution.