Measurements of the saturation magnetization have been made on a series of Fe-Si alloys near ${\mathrm{Fe}}_3$Si and a series of alloys in which a small amount of a $3d$, $4d$, or $5d$ transition-metal element ($T$) is added to form the composition ${\mathrm{Fe}}_{3-c}{T}_c\mathrm{Si}$. Moment assignments of $+2.20\mathrm{}{\mu }_B$, $+1.35\mathrm{}{\mu }_B$, and $-0.07\mathrm{}{\mu }_B$ are made for the ${\mathrm{Fe}}_{\mathrm{I}}$, ${\mathrm{Fe}}_{\mathrm{II}}$, and Si sites in ordered ${\mathrm{Fe}}_3$Si. The magnetization data for Fe-Si alloys as the composition is varied about the ${\mathrm{Fe}}_3$Si stoichiometry can be fitted using a straight substitution between the ${\mathrm{Fe}}_{\mathrm{I}}$ and Si sites incorporating the above moment assignments along with a correction which reflects changes in the ${\mathrm{Fe}}_{\mathrm{II}}$ moments that depend on the local environments. The results for the ternary alloys are discussed in terms of the known site selection preference for substituted elements ($T$), their effective moments, and the disturbances of neighboring Fe moments. In particular, V, Mn, and Ti enter the ${\mathrm{Fe}}_{\mathrm{I}}$ site with moments of 0.00, +2.20${\mathrm{\mu }}_{\mathit{B}}$, and -0.73${\mathrm{\mu }}_{\mathit{B}}$, respectively, while Co enters the ${\mathrm{Fe}}_{\mathrm{II}}$ sites with a moment of +1.70${\mathrm{\mu }}_{\mathit{B}}$. These moment assignments are consistent with recent NMR data. The reslts are compared with similar measurements on binary alloys formed by adding small amounts of the various transition elements to Fe.

• Received 15 September 1975

DOI:https://doi.org/10.1103/PhysRevB.13.4060