The paper presents results of the ab initio electronic structure calculations performed for the (Fe0.5Mn0.5)2P0.67Ge0.33 alloy, a member of (Fe1−xMnx)2P1−yGey family of alloys showing a giant magnetocaloric eect. Calculations conrmed the strong relationship between the magnetic state and crystal structure of the alloy. To investigate the isostructural phase transition driven by external magnetic eld observed in (Fe0.9Mn1.1)P0.8Ge0.2 we utilized the xed spin moment approach. Total energy analysis conrmed the occurrence of isostructural phase transition.

The ab initio study of electronic and magnetic properties of (Gd1−xYx)7Pd3 alloys are presented. The electronic structure calculations were performed using FP-LAPW method. Basing on the ground-state single-electron results the many particle sf model for disordered alloy with strongly correlated band electrons was parameterized. The concentration dependence of the band structure, magnetic moment, and the Curie temperature is presented and discussed in reference to experimental data.

The investigations of the hyperfine interactions in Pt3Fe with the noncollinear magnetic order by means of ab initio methods are presented. It is shown that the ground state magnetic order of Pt3Fe is of noncollinear character. Electric field gradient and hyperfine magnetic field at 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.

We present the ab initio investigations of the electronic and magnetic properties of magnetocaloric Gd(Ni1−xFex)3 alloys. To simulate fractional concentrations the supercell approach was implemented and dierent congurations of iron atoms were considered. Energetical analysis of site preference and magnetic order was performed. The concentration dependence of the averaged total and local magnetic moments and of the valence band photoemission spectra are presented and discussed in reference to experimental data.