Structural, Magnetic and Electrical Properties of the Ternary Silicide Gd6Co1.67Si3 Derived from the Hexagonal Ho4Co3.07 (or Ho6Co4.61) Type Structure

The title compound was discovered as an impurity phase in many GdCoSi samples. It crystallizes in the hexagonal space group P6 3 /m with a = 11.7787(5) and c = 4.1640(2) Å . Using X-ray powder diffraction, an ordered distribution between Co and Si was found but one site is not fully occupied by Co for steric reasons. Magnetization measurements reveal that Gd 6 Co 1.67 Si 3 exhibits a ferromagnetic transition at TC = 294(2) K, a Curie temperature similar to that reported for pure gadolinium. This magnetic ordering has been confirmed by electrical resistivity investigations.