Mathematics & Physics 2017, 10(1), 51–54 УДК 517.9 Ab Initio Investigation of the Spin-Reorientation Phase Transition in PrCo5−xNix (x = 0-5) Alexey V.Lukoyanov∗ Institute of Metal Physics UB RAS Kovalevskaya, 18, Yekaterinburg, 620990 Institute of Physics and Technology Ural Federal University Mira, 19, Yekaterinburg, 620002 Russia Received 20.08.2016, received in revised form 10.10.2016, accepted 14.12.2016 The series PrCo5−xNix (x = 0-5) was investigated within the LDA+U+SO method taking into account strong correlations and spin-orbit coupling in Pr-4f, as well as in Ni(Co)-3d states. <...> We give a detailed description of total energies, electronic structure and magnetic moments directions and values for all ions and concentrations considered. <...> It was obtained that the system pass through a continuous spin transition from planar ab to the c axis directions of the Pr ion in agreement with experiments. <...> Physical properties of intermetallic compounds of the series RNi5, where R is a rare-earth metal, are well-known to be significantly transformed by substitutional d or p metals due to some changes in the electronic structure, exchange interactions and crystalline field [1]. <...> In some cases, impurities and substitutions can induce changes of electronic, magnetic and crystal parameters that improve functional properties of these alloys. <...> The concentration changes of the electronic and magnetic properties in the pseudobinary systems PrNi5−xCux [5] and PrNi5−xCox [2] have been found to be substantial at the temperature and increase of the impurity ions concentration. <...> The growth of the substitution ion concentration results in the non-monotonous behavior of spontaneous magnetic moment, magnetic susceptibility, Curie temperature, as well as structural and electronic parameters in this system. <...> In the parent binary compound PrNi5 for all temperatures the total magnetic moment of the Pr ion is frozen. <...> At the same time even small concentrations of Co or Cu in this compound give rise to the ferromagnetic state with the increase of the 3d band susceptibility and exchange interactions in the 3d subsystem. <...> In the PrNi5−xCox system the Curie temperature has very high values and grows from 60 up to 540 K for the cobalt concentration range x=1.95ч3. <...> In PrCo5 magnetic moment is along the easy axis c, this trend remains for a slight <...>