Theoretical investigation of the structural, electronic, magnetic and elastic properties of binary cubic C15-Laves phases TbX2 (X = Co and Fe)

Bentouaf, Ali; Mebsout, R.; Rached, H.; Amari, S.; Reshak, A.H.; Aïssa, Brahim

doi:10.1016/j.jallcom.2016.08.046

Cited by 42 publications

(22 citation statements)

References 38 publications

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“…Complementary, electronic structure calculations leading to derive theoretical trends of the magnetic and elastic properties e.g., as recently reported for TbFe 2 and TbCo 2 systems in ref. [71] should be of interest to compare after using a KKR-CPA code, the present Er(Fe 1−x TM x ) 2 compounds, as well to their hydrides.…”

Section: Discussionmentioning

confidence: 99%

Magnetic and Magnetocaloric Effect of Laves Phase Compounds Er(Fe0.8−xMn0.2−yCox+y)2 with x, y = 0.0 or 0.1

Othmani

Chaaba²,

Haj-Khlifa

et al. 2020

Metals

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Magnetic and magnetocaloric effect (MCE) of the Er(Fe0.8−xMn0.2−yCox+y)2 Laves phase-type compounds have been investigated. X-ray diffraction (XRD) analysis has revealed that these compounds crystallize with the C15 type Laves phase structure (Space Group Fd-3m). The magnetization curves indicate a ferri-magnetic-ordering resulting of the antiparallel coupling between the moments of the heavy rare earth Er and the transition metal (TM). The partial substitution of Fe/Mn by Co increases the Curie temperature from 355 K for Er(Fe0.8Mn0.2)2 to 475, 550, and 555 K for Er(Fe0.7Mn0.2Co0.1)2, Er(Fe0.8Mn0.1Co0.1)2, and Er(Fe0.7Mn0.1Co0.2)2, respectively. According to the nature of the TM elements, arguments were presented forwards either Molecular Field or Spin Fluctuation Theory, even Stoner type pictures should be considered for. MCE was calculated according to the Maxwell relation based on isotherm magnetization measurements. The magnetic entropy change (−∆SM) observed on a 300–400 K temperature range can be understood in terms of a Spin Fluctuation Theory picture supported by both the different magnetic polarization levels that were shared by the TM elements and the related interatomic exchange forces.

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Section: Discussionmentioning

confidence: 99%

Magnetic and Magnetocaloric Effect of Laves Phase Compounds Er(Fe0.8−xMn0.2−yCox+y)2 with x, y = 0.0 or 0.1

Othmani

Chaaba²,

Haj-Khlifa

et al. 2020

Metals

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“…Ideally, we should calculate these constants from first principles. However, even obtaining zero-temperature elastic constants for the stoichiometric end compounds TbFe 2 and DyFe 2 in DFT is not straightforward due to the difficulty in treating the RE-4f electrons [30]. [26].…”

Section: Elastic Energymentioning

confidence: 99%

“…[26]. We test the sensitivity of our results to this choice by calculating spin-orientation diagrams using different sets of elastic constant values, which are either obtained from DFT or measured experimentally, for different compositions [30,31]. The comparison is provided as an Appendix and shows the sensitivity to be very weak.…”

Section: Elastic Energymentioning

confidence: 99%

“…Here, we illustrate the effect on the spin-orientation diagram of using different values for these constants. Table II lists elastic constants either measured experimentally for Tb 0.3 Dy 0.7 Fe 2 and DyFe 2 [26] or calculated within DFT for TbFe 2 and YFe 2 [30,31]. For the DFT calculations, a generalized-gradient approximation (GGA) is used for the exchange correlation.…”

Section: Appendix: Elastic Constantsmentioning

confidence: 99%

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Spin Orientation and Magnetostriction of Tb1−xDyxFe2 from First Principles

2020

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The optimal amount of dysprosium in the highly magnetostrictive rare-earth compounds Tb 1−x Dy x Fe 2 for room-temperature applications has long been known to be x = 0.73 (Terfenol-D). Here, we derive this value from first principles by calculating the easy magnetization direction and magnetostriction as a function of composition and temperature. We use crystal-field coefficients obtained within density-functional theory to construct phenomenological anisotropy and magnetoelastic constants. The temperature dependence of these constants is obtained from disordered-local-moment calculations of the rare-earth magnetic order parameter. Our calculations find the critical Dy concentration required to switch the magnetization direction at room temperature to be x c = 0.78, with magnetostrictions λ 111 = 2700 and λ 100 = −430 ppm, close to the Terfenol-D values.

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“…Большая вариативность физических свойств соединений YFe 2 и TbFe 2 стимулирует интерес к исследованию их электронной структуры. С использованием различных вычислительных методов были выполнены расчеты энергетических спектров данных материалов [15][16][17][18][19][20][21], в которых определена природа и особенности электронных состояний вблизи уровня Ферми E F . Для изучения электронной структуры YFe 2 и TbFe 2 в различных областях энергетического спектра применялись также фотоэмиссионные [22][23][24] и спектральные [10,11,25] методы.…”

Section: Introductionunclassified

Оптические свойства соединений YFe-=SUB=-2-=/SUB=- и TbFe-=SUB=-2-=/SUB=-

Князев¹,

Кузьмин²

2020

Физика Твердого Тела

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Ellipsometric investigation of the optical properties of YFe2 and TbFe2 intermetalic compounds have been carried out in wavelength range of 0.22 –15 μm. A number of electronic and spectral characteristic was determined. Nature of interband light absorption in these materials is discussed on base of comparative analyses of experimental and theoretical optical conductivity spectra. Experimental optical conductivities of the compounds are shown to conform qualitatively to spectra calculated from densities of electronic states in the region of quantum electron transitions.

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Theoretical investigation of the structural, electronic, magnetic and elastic properties of binary cubic C15-Laves phases TbX2 (X = Co and Fe)

Cited by 42 publications

References 38 publications

Magnetic and Magnetocaloric Effect of Laves Phase Compounds Er(Fe0.8−xMn0.2−yCox+y)2 with x, y = 0.0 or 0.1

Magnetic and Magnetocaloric Effect of Laves Phase Compounds Er(Fe0.8−xMn0.2−yCox+y)2 with x, y = 0.0 or 0.1

Spin Orientation and Magnetostriction of Tb1−xDyxFe2 from First Principles

Оптические свойства соединений YFe-=SUB=-2-=/SUB=- и TbFe-=SUB=-2-=/SUB=-

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