Showing papers by "Mikhail A. Zagrebin published in 2017"
TL;DR: In this article, a systematic ab initio calculations based on the DFT methodology and Spin-Polarized Relativistic Korringa-Kohn-Rostoker method are carried out to investigate magnetic properties of structure-disordered Ni-Mn-Ga Heusler alloys.
11 citations
TL;DR: In this paper, the effects of structural disorder on the magnetic and electronic ground state properties of Co2CrAl Heusler alloy were studied by means of ab initio and Monte Carlo methods.
Abstract: In order to discuss the difference between the available theoretical and experimental values of the total magnetic moment of Co2CrAl Heusler alloy, in this paper we studied the effects of a structural disorder on the magnetic and electronic ground state properties of the alloy studied by means of ab initio and Monte Carlo methods On the one hand, it is shown that a calculated magnetic ground state of the austenite L21 structure is ferromagnetic, and the alloy demonstrates half-metallic behavior However, the equilibrium lattice parameter and magnetic moment calculated for ferrimagnetic state (where the Cr atoms are ordered antiferromagnetically) are in better agreement with the available experimental data than the ferromagnetic one On the other hand, an account of a structural disorder results in a decrease in the magnetic moment to a value close to the experimental However, systems with a structural disorder are energetically unfavorable in comparison with the ordered L21 structure at zero temperature Using the calculated exchange coupling parameters in the Heisenberg Hamiltonian, the temperature dependences of magnetization, specific heat, magnetic part of internal energy as well as Helmholtz energy are simulated in the framework of Monte Carlo technique for both ordered and disordered cases Eventually, it is shown that the disordered structure with smaller magnetization is more stable at higher temperatures This indicates that the experimental compound might be disordered
10 citations
TL;DR: In this paper, the magnetic states of ternary Ni 2 Cr Z (Z ǫ=Al, As, Bi, Ga, Ge, In, P, Pb, Sb, Si, Sn, Tl) were compared with Ni 2 Mn Z ones by ab initio methods.
9 citations
TL;DR: In this article, the crystal lattice parameters, tetragonality degree, magnetic moments, magnetic exchange parameters in the Ni7Co1Mn5Cr1Sn2 Heusler alloy are investigated by ab initio calculations and supercell approach.
9 citations
TL;DR: In this article, the crystal structure, magnetic and magnetocaloric properties of Co-doped Ni-Mn-(Sn, Al) Heusler alloys were calculated using ab initio zero-temperature calculations combined with Monte Carlo finite-time simulations.
9 citations
27 Feb 2017
9 citations
TL;DR: In this article, the structural and magnetic properties of Mn-and Pt-doped Fe-Rh alloys are investigated by first principles calculations, and it is shown that an increase in Mn content leads to increase in the energy difference between cubic and tetragonal phases which is equivalent of increase in a temperature of structural transformation.
8 citations
TL;DR: In this article, a theoretical study of magnetic properties for Fe 100 - x Ga x (x ǫ = 25, 28.125%) alloys in the framework of first-principles calculations and Monte Carlo simulations is presented.
8 citations
8 citations
TL;DR: In this paper, a series of Ni8Mn2 Cr 2 Z 4 alloys with partial replacing of Mn by Cr is studied to investigate the effect of such substitution on their structural and magnetic properties.
7 citations
TL;DR: In this article, the magnetic and structural properties of a series of nonstoichiometric Ni-Mn-Ga Heusler alloys are theoretically investigated in terms of the density functional theory.
Abstract: The magnetic and structural properties of a series of nonstoichiometric Ni–Mn–Ga Heusler alloys are theoretically investigated in terms of the density functional theory. Nonstoichiometry is formed in the coherent potential approximation. Concentration dependences of the equilibrium lattice parameter, the bulk modulus, and the total magnetic moment are obtained and projected onto the ternary phase diagram of the alloys. The stable crystalline structures and the magnetic configurations of the austenitic phase are determined.
TL;DR: In this paper, the role of the atomic disorder in the phonon instabilities that are characteristic for some Heusler alloys has been investigated with PHONON and VASP software.
TL;DR: In this article, it was shown that Ni-Mn(Cr) pairs show the strongest ferromagnetic exchange interaction between nearest neighbor atoms in austenite of all alloys considered, and the most part of total spin up and spin down density of states is caused by Ni atoms.
TL;DR: In this article, the magnetic, structural and thermodynamic properties in a series of Mn 3 -X-C (X = Ga, Sn) have been studied by means of first-principles based on the density-functional theory and quasi-harmonic approximations based on Debye model.
Abstract: In this work, the magnetic, structural and thermodynamic properties in a series of Mn 3 -X-C (X = Ga, Sn) have been studied by means of first-principles based on the density-functional theory and quasi-harmonic approximations based on the Debye model. To evaluate the magnetic effects, first-principles calculations have been carried out for different magnetic spin configurations including ferro- and ferrimagnetic configurations as well as different non-colinear ones. It has been shown that for both compounds the non-colinear spin orderings with a lower magnetic moment are favorable configurations at zero-temperature as compared with the ferromagnetic one. The magnetic exchange coupling constants showing an oscillation behavior becomes weaker along the sequence of Mn 3 -Ga-C → Mn 3 -Sn-C. Using the thermodynamic approach, the magnetic phase transition between ferromagnetic and non-colinear states in Mn 3 -Ga-C is found. While for Mn 3 -Sn-C, this transition does not occur in a studied temperature range. The pressure effect on the thermodynamic properties has been estimated. The calculated results are in a good agreement with available experimental data.
01 Apr 2017
TL;DR: In this article, magnetostrictive actuators are used as sensors in micro electro-mechanical systems and sensor devices, and they are shown promising for use as sensors.
Abstract: Nowadays, magnetostrictive materials are promising for use as sensors, magnetostrictive actuators, in micro electro-mechanical systems and sensor devices.
TL;DR: In this paper, the authors reported results of ab initio calculations of structural and magnetic properties in a series of Heusler compositions Ni2+xMn1-x(Ga, Ge).