Stoner theory support for the two-state hypothesis for γ iron

Roy, D. M.; Pettifor, D. G.

doi:10.1088/0305-4608/7/7/004

Cited by 72 publications

(15 citation statements)

References 12 publications

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“…We see that canonical Stoner theory predicts that the magnetic moment of bcc iron decreases gradually with de- Table II, respectively. creasing normalized exchange integral ͑or volume͒, whereas the two close-packed structures fcc and hcp initially fall precipitously at some critical value of normalized exchange integral ͑or volume͒. These k-space TB predictions, first made 30 years ago, 57,58 were later confirmed by first-principles density-functional theory ͑see, for example, Ref. 59͒.…”

Section: B Magnetic Momentsmentioning

confidence: 83%

“…This dependence follows directly from the Stoner model of itinerant magnetism 54 which predicts the self-consistent ferromagnetic moment is determined by the condition [55][56][57][58] In s ͑E F ͒ = 1, ͑43͒…”

Section: B Magnetic Momentsmentioning

confidence: 88%

“…Within canonical d-band theory the shape of the density of states remains unaltered as the volume changes, so that the Stoner condition, Eq. ͑43͒ may be rewritten 57,58 in terms of the dimensionless density of states per spin n s ͑⑀͒, namely ͓I/͑2b 1 ͔͒n s ͑⑀ F ,m͒ = 1, ͑45͒…”

Section: B Magnetic Momentsmentioning

confidence: 99%

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Valence-dependent analytic bond-order potential for transition metals

Drautz

Pettifor

2006

Phys. Rev. B

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An analytic interatomic bond-order potential is derived that depends explicitly on the valence of the transition-metal element. It generalizes the second-moment Finnis-Sinclair and fourth-moment Carlsson potentials to include higher moments. We find that the sixth-moment approximation predicts not only the structural trend from hcp→ bcc→ hcp→ fcc that is observed across the nonmagnetic 4d and 5d transition-metal series, but also the different ferromagnetic moments of the bcc, fcc, and hcp phases of the 3d transition-metal iron. An analytic expression for the force is obtained and proved to converge to the Hellmann-Feynman force as higher moments are included.

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Section: B Magnetic Momentsmentioning

confidence: 83%

Section: B Magnetic Momentsmentioning

confidence: 88%

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Valence-dependent analytic bond-order potential for transition metals

Drautz

Pettifor

2006

Phys. Rev. B

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“…This is a transition of the same kind as has been discussed for the fcc FeNi random alloy. 11,16,17,29 In the fcc phase it is related to the particular shape of the fcc state density and the position of the Fermi level 3,30 which for Fe results in the existence of three ͑meta-stable͒ solutions with different values of the magnetic moments at different Wigner-Seitz radii. In pure fcc Fe the LS solution has the lowest energy, but when one adds Co ͑or Ni͒, the energy difference between the HS and the LS states decreases, and for 45% of Co the HS solution becomes more stable.…”

Section: Resultsmentioning

confidence: 99%

Magnetically induced crystal structure and phase stability inFe1−cCo<

et al. 1996

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We present an ab initio determination of the crystallographic phase stability of Fe-Co alloys as a function of concentration, using the coherent potential approximation. A bcc → hcp phase transition is found at a concentration of 85 at. % of Co, in good agreement with the experimental phase diagram. We demonstrate that for the Fe-rich random alloys magnetism stabilizes the bcc phase relative to the close-packed fcc and hcp phases. Magnetism also favors the partially ordered ␣Ј phase relative to the random bcc alloy. This unique relation between magnetism and phase stability for the Fe-Co alloys is analyzed by a spin-polarized canonical d-band model. ͓S0163-1829͑96͒09326-5͔

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“…This general behavior of the total energy on volume for the ferromagnetic solution is in agreement with earlier studies. 20,27,28,[59][60][61][62][63][64][65][66][67][68][69] We also included a collinear antiferromagnetic state, with magnetic moments ordered parallel to FIG. 1.…”

Section: Analysis Of the Approximations Involved In The Simulatimentioning

confidence: 99%

Competition between magnetic structures in the Fe rich fcc FeNi alloys

et al. 2007

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We report on the results of a systematic ab initio study of the magnetic structure of Fe rich fcc FeNi binary alloys for Ni concentrations up to 50 at. %. Calculations are carried out within density-functional theory using two complementary techniques, one based on the exact muffin-tin orbital theory within the coherent potential approximation and another one based on the projector augmented-wave method. We observe that the evolution of the magnetic structure of the alloy with increasing Ni concentration is determined by a competition between a large number of magnetic states, collinear as well as noncollinear, all close in energy. We emphasize a series of transitions between these magnetic structures, in particular we have investigated a competition between disordered local moment configurations, spin spiral states, the double layer antiferromagnetic state, and the ferromagnetic phase, as well as the ferrimagnetic phase with a single spin flipped with respect to all others. We show that the latter should be particularly important for the understanding of the magnetic structure of the Invar alloys.

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Stoner theory support for the two-state hypothesis for γ iron

Cited by 72 publications

References 12 publications

Valence-dependent analytic bond-order potential for transition metals

Valence-dependent analytic bond-order potential for transition metals

Magnetically induced crystal structure and phase stability inFe1−cCo<

Competition between magnetic structures in the Fe rich fcc FeNi alloys

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