2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/168334Local perturbations of crystal and magnetic structure of $γ$-iron near carbon interstitial impurity is investigated by {\it ab initio} electronic structure calculations. It is shown that the carbon impurity creates locally a region of ferromagnetic ordering with substantial tetragonal distortions. Exchange integrals and solution enthalpy are calculated, the latter being in a very good agreement with experimental data. Effect of the local distortions on the carbon-carbon interactions in $γ$-iron is discussed.4 pages 3 figures. Final version, accepted to Phys.Rev. LettMaterials Sciencetext