Structural and Magnetic Properties of Mn-Co-C Alloys

${\mathrm{Mn}}_{\mathrm{X}}{\mathrm{Co}}_{\text{(80−}\mathrm{X})}{\mathrm{C}}_{20}$ alloys were studied for magnetic properties, crystal structure, and metallographic appearance. A superlattice having the stoichiometric composition ${\mathrm{Mn}}_2{\mathrm{Co}}_2\mathrm{C}$ was found to be markedly magnetic. The structure of this alloy is pseudo‐f.c.c. with the C atom in the central $\frac{1}{2}$ $\frac{1}{2}$ $\frac{1}{2}$ position, the Mn atoms in the 000 and $\frac{1}{2}$ $\frac{1}{2}$ 0 sites, and the Co atoms in the 0$\frac{1}{2}$ $\frac{1}{2}$ and $\frac{1}{2}$ 0$\frac{1}{2}$ sites. A magnetic structure was deduced from a consideration of the effect of atomic separation on magnetic vector alignment and an indication that electrons transfer from the central C atom to its nearest neighbors, the face atoms.