MAGNETIC PROPERTIES OF COSEXS2-X

Single crystals of the solid solutions CoSexS2-x, 0≤x≤0.25 and a well homogenized powder sample with x=0.30 have been studied by magnetization and susceptibility measurements between 4.2° and 300°K. Over the range 0≤x≤0.20 the Curie temperature decreases linearly, while the moment remains constant at 0.88±0.02 μB/Co atom at 4.2°K. For compositions with x>0.20 both TC and the moment, σ4.2°,10kOe, decrease rapidly, and at x=0.30 no well-defined ferromagnetic transition temperature was observed down to 4.2°K. The limit of existence of ferromagnetism in this system at 0°K appears to be close to x=0.20. The reduced moment observed for apparently homogeneous preparations with x=0.22 and 0.25 is suggestive of a noncollinear spin arrangement at low temperatures for these compositions. For 0.20≤x≤0.30 a minimum is observed in the χM-1, T curve, in some cases above a well defined lower ferromagnetic transition temperature. © 1969 The American Institute of Physics.