The formation and magnetic properties of Dy₂Fe₁₇C_x with high carbon content obtained by rapid solidification

The carbides Dy₂Fe₁₇C_x with x=1.5-3.0 have been successfully prepared by the melt-spinning method. The X-ray diffraction patterns and the thermomagnetic curves show that they are of single phase in general with Th₂Zn₁₇ structure type when x=1.5, 2.0, 2.5 and 2.8 with a small amount of alpha -Fe as an impurity phase, while for x=3.0 the proportion of the alpha -Fe phase is high. The lattice parameters a and c are both enlarged and increase with the carbon content x. The Curie temperatures T_c are greatly enhanced when x<2.5 and remain almost constant when x=2.5-3.0, but the saturation magnetizations, sigma _s, increase slightly. The Dy₂Fe₁₇C_x ribbons still maintain the rhombohedral Th₂Zn₁₇-type structure after being annealed at 1100 degrees C for 14 h, which indicates the high stability of Dy₂Fe₁₇C_x (x=1.5-3.0) compounds obtained by rapid solidification. The heat-treated ribbon samples can be magnetically oriented and prefer an easy-plane anisotropy at room temperature.