MAGNETIC-PROPERTIES OF TM2FE17CX LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-2.8) COMPOUNDS PREPARED BY MELT-SPINNING

The formation, structure, and magnetic properties of Tm2Fe17Cx compoun ds with x=0, 0.5, 1.0, 1.5, 2.0, 2.5, and 2.8 were studied. The sample s with x less than or equal to 1 were are melted and heat treated at 1 370 K for 14 h. The carbides were prepared by melt spinning at appropr iate quenching rates of v(s)=10-20 m/s for 1.5 less than or equal to x less than or equal to 2.5 and by the crystallization from correspondi ng amorphous for x=2.8. X-ray diffraction and thermomagnetic measureme nts show that all samples studied are single phase with the hexagonal Th2Ni17-type structure except for Tm2Fe17C2.8, which contains a few pe rcent of alpha-Fe. The lattice parameters a,c and the unit-cell volume s v increase as the carbon concentration x increases. The Curie temper ature is found to rise with x from 260 K for x=O to 669 K for x=2.8. T he saturation magnetization M(s) at 1.5 K is found to be 92.2-97.1 emu /g as x varies from 0 to 2.8, and the carbon concentration dependence of the Fe moment is approximately constant (2.12+/-0.04 mu(B)). The sp in-reorientation transitions are observed. The spin-reorientation temp erature is found to increase with the carbon concentration for x less than or equal to 1.5, and then has a slight decrease with x for x>1.5.