Phase diagram of magnetostrictive Fe-Ga alloys: insights from theory and experiment

Matyunina, M. V.; Загребин, М. А.; Sokolovskiy, V. V.; Pavlukhina, Oksana; Buchelnikov, V. D.; Балагуров, А.М.; Golovin, I.S.

doi:10.1080/01411594.2018.1556268

Cited by 43 publications

(15 citation statements)

References 28 publications

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“…%). The same concentration dependencies for both C' and C 44 were obtained theoretically for the D0 3 phase in the Fe-Ga system [24]. In the case of A2 and L1 2 structures, the tetragonal shear modulus decreases in the considered range of 12,5 ≤ x ≤ 28,125 at.%.…”

Section: Calculation Resultssupporting

confidence: 74%

Structural and Elastic Properties of Fe-Ge Alloys: ab initio studies

Загребин¹,

Matyunina²,

Sokolovskiy³

et al. 2020

MMPh

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In this paper, with the help of the density functional theory, the structural and elastic properties of A2, B2, D0 3 , and L1 2 phases of Fe 100-x Ge x alloys (12,5 ≤ x ≤ 28,125 at. %) have been studied. The electronic and full ionic relaxations were used for the investigation of crystal structures. The concentration dependencies of the atomic volumes, structural phase transition temperatures, tetragonal and rhombohedral shear moduli have been calculated. We show that the atomic volume curves correlate with the sequence of phase transitions observed experimentally: A2→B2→D0 3 (x ≤ 22 at. % of Ge content). The structural phase transition temperatures increase with the Ge concentration. The calculated tetragonal moduli for the D0 3 , A2, and L1 2 structures decrease with the increasing of the Ge content, what agrees with the experimental results. The dependence of rhombohedral shear moduli as a function of Ge concentration does not change significantly with increasing Ge atoms. The C 44 is increased for the D0 3 phase, while for A2, B2, and L1 2 , it decreases.

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Section: Calculation Resultssupporting

confidence: 74%

Structural and Elastic Properties of Fe-Ge Alloys: ab initio studies

Загребин¹,

Matyunina²,

Sokolovskiy³

et al. 2020

MMPh

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“…structure, which in the case of simple metals is less densely packed than f.c.c. The calculations by means of density functional theory (Matyunina et al, 2019) confirm this effect, which is evidence of its association with the features of the electron distribution in these alloys.…”

Section: Figuresupporting

confidence: 53%

The first- and second-order isothermal phase transitions in Fe₃Ga-type compounds

Балагуров

Samoylova

Бобриков

et al. 2019

Acta Crystallogr Sect B

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Structural features and kinetics of the transition between ordered metastable b.c.c.‐derived D03 and equilibrium f.c.c.‐derived L12 phases of Fe–xGa alloys (x = 27.2% and 28.0%) have been analyzed by in situ real‐time neutron diffraction during isothermal annealing in the temperature range 405–470°C. It has been revealed that the transition proceeds with alternation of the first‐ and second‐order phase transformations according to a D03 → A2 → A1 → L12 scheme, where A2 and A1 are disordered b.c.c. and f.c.c. structures. Deformations of the crystal lattice that arise due to these transitions are determined. The kinetics of the L12 phase nucleation and growth were analyzed in the frame of the Johnson–Mehl–Avrami–Kolmogorov (JMAK) model; however, only the early stage of the D03 → L12 transition is well described by the JMAK equation. The value of the Avrami exponent corresponds to the constant growth rate of the new L12 phase and decreasing nucleation rate in the Fe–27.2Ga alloy and indicates the presence of pre‐existing nucleation centres of the L12 phase in the Fe–28.0Ga alloy.

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“…Для вычислений использовалась сетка, содержащая набор k-точек 8 × 8 × 8, сгенерированная по схеме Монхроста-Пака [12]. Геометрическая оптимизация выполнена для структур, наблюдаемых экспериментально [13]. Равновесные параметры решетки a 0 и энергия E 0 были оценены для всех рассмотренных фаз согласно уравнению состояния Берча-Мурнагана.…”

Section: детали вычисленийunclassified

Фазовые превращения в сплавах Fe-=SUB=-100-x-=/SUB=-Si-=SUB=-x-=/SUB=-: исследования ab initio

Загребин¹,

Матюнина²,

Кошкин³

et al. 2020

Физика Твердого Тела

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Поступила в Редакцию 30 декабря 2019 г. В окончательной редакции 30 декабря 2019 г. Принята к публикации 10 января 2020 г.На основе температур структурных и магнитных фазовых переходов, оцененных теоретически из первых принципов, построена фазовая диаграмма концентрации для сплавов Fe 100−x Six (9.375 ≤ x ≤ 25.0 at.%). Температуры структурного фазового перехода для экспериментально наблюдаемых кристаллических структур получены из геометрической оптимизации кристаллической структуры. Температуры Кюри оценивались в приближении молекулярного поля с использованием констант магнитного обменного взаимодействия, рассчитанных ab initio. Во всем рассматриваемом интервале концентраций структурные переходы из упорядоченной кубической фазы в полностью разупорядоченную через частично неупорядоченную происходят с ростом температуры. Что касается магнитных превращений, то переход ферромагнетик-парамагнетик наблюдается для всех составов, однако в разных кристаллических фазах.Ключевые слова: фазовая диаграмма, ab initio, кристаллическая структура, обменное взаимодействие, приближение молекулярного поля.

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Phase diagram of magnetostrictive Fe-Ga alloys: insights from theory and experiment

Cited by 43 publications

References 28 publications

Structural and Elastic Properties of Fe-Ge Alloys: ab initio studies

Structural and Elastic Properties of Fe-Ge Alloys: ab initio studies

The first- and second-order isothermal phase transitions in Fe₃Ga-type compounds

Фазовые превращения в сплавах Fe-=SUB=-100-x-=/SUB=-Si-=SUB=-x-=/SUB=-: исследования ab initio

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Phase diagram of magnetostrictive Fe-Ga alloys: insights from theory and experiment

Cited by 43 publications

References 28 publications

Structural and Elastic Properties of Fe-Ge Alloys: ab initio studies

Structural and Elastic Properties of Fe-Ge Alloys: ab initio studies

The first- and second-order isothermal phase transitions in Fe3Ga-type compounds

Фазовые превращения в сплавах Fe-=SUB=-100-x-=/SUB=-Si-=SUB=-x-=/SUB=-: исследования ab initio

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The first- and second-order isothermal phase transitions in Fe₃Ga-type compounds