Effect of Noncollinear Magnetic Order on the Hyperfine Interactions in $Pt_{3}Fe$

The investigations of the hyperfine interactions in $Pt_{3}Fe$ with the noncollinear magnetic order by means of ab initio methods are presented. It is shown that the ground state magnetic order of $Pt_{3}Fe$ is of noncollinear character. Electric field gradient and hyperfine magnetic field at $\text{}^{57}Fe$ nucleus were calculated and their dependence on the strength of Coulomb correlation interaction is discussed. The calculated values of electric field gradient correspond with the experimental data and the best agreement was found when the enhanced Coulomb correlation interaction for 3d-states of Fe was considered. Lattice, local valence electron (3d, 4p) and weakly bound 3p semicore electron contributions to electric field gradient are separated out and discussed.