Moment Formation and Itinerant Ferromagnetism in the FeSi[Single Bond]CoSi Mixed System: Co59 NMR

The magnetic properties of Co atom in both paramagnetic and ferromagnetic phases of the $({\mathrm{Fe}}_{\text{1−}\mathrm{x}}{\mathrm{Co}}_{\mathrm{x}})\mathrm{Si}$ solid solution have been investigated by the Co⁵⁹ NMR. From aie spin‐echo intensity analysis, it is concluded that the Co atom becomes magnetic when it has one or more Fe atoms in its n.n. metal sites and otherwise remains nonmagnetic. The hyperfine field at Co atom is about 9 KOe for the alloy with x of 0.3 and increases monotonically with increasing Fe concentration.