MAGNETIC HARDENING OF SM2FE17-XGAXC2.5 COMPOUNDS

The structure and magnetic properties of Sm2Fe17-xGaxC25 (x=2, 3, 4 an d 5) compounds prepared by arc-melting were studied. X-ray diffraction shows that these samples are single phase with rhombohedral Th2Zn17-t ype structure. The unit-cell volumes nu of Sm2Fe17-xGaxC25 compounds i ncrease monotonically with increasing Ga concentration from 832.7 Angs trom(3) for x=2 to 837.4 Angstrom(3) for x=5. The Curie temperature T- c and room temperature saturation magnetization M(s) are found to decr ease monotonically with increasing Ga concentration. The Sm2Fe17-xGaxC 25 compounds exhibit an easy c-axis anisotropy at room temperature. Th e anisotropy field is 135 kOe for x=2, and decreases to 76 kOe at x=4. A room temperature coercivity exceeding 13 kOe is obtained in as-quen ched Sm2Fe17-xGaxC25 ribbons with x=2 and x=3.