Both collinear and noncollinear magnetic structures of FeMn with ${L1\mathrm{}}_0$ atomic ordering were determined from total-energy full-potential linearized augmented plane-wave calculations incorporating noncollinear magnetism with no shape approximation for the magnetization density. Different spin-density orientations for the different band states are observed on a smaller length scale inside an atom. The presence of the intra-atomic noncollinear magnetism enhances the stability of the $3Q$ noncollinear magnetic structure, in which the magnetic moments align toward the center of the cell of four atoms, thus becoming the lowest-energy state of the structures considered.

• Received 27 September 2002

DOI:https://doi.org/10.1103/PhysRevB.67.014405