Dependence of magnetism of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">V</mml:mi><mml:msub><mml:mi mathvariant="normal">Au</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>alloy on the state of chemical order: A first principles study

Khmelevska, T.; Khmelevskyi, Sergii; Ruban, Andrei V.; Mohn, P.

doi:10.1103/physrevb.76.054445

Cited by 8 publications

(5 citation statements)

References 21 publications

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“…The energy differences are somewhat smaller than the respective values calculated for Fe-Si alloys. 32 However, these differences in ordering energies calculated for the paramagnetic state with disordered local moments ͑black symbols, Fig. 2͒ are about two times smaller than respective differences in Fe-Si.…”

Section: Chemical Ordering and Magnetism On Fe Sublatticesmentioning

confidence: 81%

Magnetism and structural ordering on a bcc lattice for highly magnetostrictive Fe–Ga alloys: A coherent potential approximation study

Khmelevska

Khmelevskyi

Mohn

2008

Journal of Applied Physics

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We calculate the electronic structure, magnetic moments, and ordering energies of highly magnetostrictive Fe 1−x Ga x alloys from first-principles in the composition range up to x = 0.25. The coherent potential approximation was used to treat effects of chemical disorder. Given an underlying bcc lattice in whole range compositions investigated, the DO 3 type of ordering is found to have a lower energy than A2-and B2-type structures. We find that ordering energies strongly depend on the state of magnetic order such that thermal magnetic disorder strongly favors chemical ordering ͑DO 3 and B2͒. The values of the magnetic moments of Fe on different sublattices of ordered structures are found to have a distinctive dependency on the Ga concentration. By taking into account the results of earlier fully relativistic and full potential calculations of magnetostriction for ordered stoichiometric Fe 3 Ga compounds and available experimental phenomenology, our results for disordered alloys suggest an eventually more complex origin of the giant magnetostriction in Fe-Ga alloys than it would appear from a simple electronic structure analysis of ordered stoichiometric compounds.

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Section: Chemical Ordering and Magnetism On Fe Sublatticesmentioning

confidence: 81%

Magnetism and structural ordering on a bcc lattice for highly magnetostrictive Fe–Ga alloys: A coherent potential approximation study

Khmelevska

Khmelevskyi

Mohn

2008

Journal of Applied Physics

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“…This happens if an alloy consists of metals such as Cr and V. The magnetic state of individual Cr atoms is very sensitive to their local environment, as was found, for instance, in the case of Pd 3 Cr [170] and bcc Fe-Cr alloys [176,177]. Although bcc V is not magnetic in the ground state, it easily gets quite a large magnetic moment in many alloy systems [170,178]. Similar behavior is also exhibited by 'ordinary' magnetic metals, such as Mn, Fe, Co and Ni, when they are alloyed with non-magnetic metals.…”

Section: Global and Local Magnetic Statementioning

confidence: 97%

Configurational thermodynamics of alloys from first principles: effective cluster interactions

2008

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Phase equilibria in alloys to a great extent are governed by the ordering behavior of alloy species. One of the important goals of alloy theory is therefore to be able to simulate these kinds of phenomena on the basis of first principles. Unfortunately, it is impossible, even with present day total energy software, to calculate entirely from first principles the changes in the internal energy caused by changes of the atomic configurations in systems with several thousand atoms at the rate required by statistical thermodynamics simulations. The time-honored solution to this problem that we shall review in this paper is to obtain the configurational energy needed in the simulations from an Ising-type Hamiltonian with so-called effective cluster interactions associated with specific changes in the local atomic configuration. Finding accurate and reliable effective cluster interactions, which take into consideration all relevant thermal excitations, on the basis of first-principles methods is a formidable task. However, it pays off by opening new exciting perspectives and possibilities for materials science as well as for physics itself. In this paper we outline the basic principles and methods for calculating effective cluster interactions in metallic alloys. Special attention is paid to the source of errors in different computational schemes. We briefly review first-principles methods concentrating on approximations used in density functional theory calculations, Green's function method and methods for random alloys based on the coherent potential approximation. We formulate criteria for the validity of the supercell approach in the calculations of properties of random alloys. The generalized perturbation method, which is an effective and accurate tool for obtaining cluster interactions, is described in more detail. Concentrating mostly on the methodological side we give only a few examples of applications to the real systems. In particular, we show that the ground state structure of Au 3 Pd alloys should be a complex long-period superstructure, which is neither DO 22 nor DO 23 as has been recently predicted.

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“…Electron doping with vanadium Ti 1−y V y Au [17] was mentioned in the Introduction. A related system VAu 4 , which is FM with an ordered moment of only 0.4 µ B /V, has been studied theoretically by Khmelevska et al [30] using the coherent potential approximation method. Categorized as a wFM, the magnetic properties had been observed to depend strongly on the degree of chemical order.…”

Section: Discussion and Summarymentioning

confidence: 99%

Probing hole-doping of the weak antiferromagnet TiAu with first principles methods

Milena

Goh²,

Pickett³

2019

J. Phys.: Condens. Matter

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We investigate hole-doping by Sc substitution for Ti in the weak antiferromagnet (wAFM) system Ti 1−x Sc x Au. Behavior reported so far fits a weak itinerant AFM picture, and experimentally leads to a quantum critical point at x c = 1 8 . Here we study supercells with several rational fractions x of Ti replaced by Sc. We find, unexpectedly, definite local momentlike behavior, e.g. magnetic moments of the Ti atom comparable to or even larger than in the bulk persist even into the Ti-poor regime of this alloy system. Itinerant signatures persist, however, as the Ti 3d projected density of states displays van Hove singularity peaks near the Fermi level in most cases, revealing a striking similarity to nonmagnetic bulk TiAu. The current picture of this system, midway between itinerant and local moment, will be provided and discussed in light of experimental observations.

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Dependence of magnetism ofVAu4alloy on the state of chemical order: A first principles study

Cited by 8 publications

References 21 publications

Magnetism and structural ordering on a bcc lattice for highly magnetostrictive Fe–Ga alloys: A coherent potential approximation study

Magnetism and structural ordering on a bcc lattice for highly magnetostrictive Fe–Ga alloys: A coherent potential approximation study

Configurational thermodynamics of alloys from first principles: effective cluster interactions

Probing hole-doping of the weak antiferromagnet TiAu with first principles methods

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