Magnetic Properties and the Critical Exponents in Terms of the Magnetocaloric Effect of Amorphous Fe40Ni38Mo4B18 Alloy

Ouahbi, S. El; Yamkane, Z.; Derkaoui, S.; Lassri, H.

doi:10.1007/s10948-021-05832-y

Cited by 12 publications

(4 citation statements)

References 17 publications

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“…It would be of interest to support our finding that the mean field theory is suitable for explaining the physical properties. Therefore, calculating some of the critical exponents 61 – 65 would be beneficial. We have calculated the exponent n in the relation: from the field dependence of ΔS m close to T c .…”

Section: Resultsmentioning

confidence: 99%

“…n = 1 + (β−1)/(β + γ) [e.g. 65 , which can be used to evaluate γ if β is calculated from the relation: or calculate β, if γ is calculated from: , where t = (T−T c )/T. We have calculated β for YFe 3 from its M-T data, in zero field, by taking the logarithm of M ~ (−t) β and performing the calculation for temperatures lower than T c .…”

Section: Resultsmentioning

confidence: 99%

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First principles and mean field study on the magnetocaloric effect of YFe3 and HoFe3 compounds

Abu-Elmagd

Hammad

Abdel-Kader

et al. 2023

Sci Rep

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In this work, the magnetothermal characteristics and magnetocaloric effect in YFe3 and HoFe3 compounds are calculated as function of temperature and magnetic field. These properties were investigated using the two-sublattice mean field model and the first-principles DFT calculation using the WIEN2k code. The two-sublattice model of the mean-field theory was used to calculate the temperature and field-dependences of magnetization, magnetic heat capacity, magnetic entropy, and the isothermal change in entropy ∆Sm. We used the WIEN2k code to determine the elastic constants and, subsequently, the bulk and shear moduli, the Debye temperature, and the density-of-states at Ef. According to the Hill prediction, YFe3 has bulk and shear moduli of roughly 99.3 and 101.2 GPa respectively. The Debye temperature is ≈ 500 K, and the average sound speed is ≈ 4167 m/s. In fields up to 60 kOe and at temperatures up to and above the Curie point for both substances, the trapezoidal method was used to determine ∆Sm. For instance, the highest ∆Sm values for YFe3 and HoFe3 in 30 kOe are approximately 0.8 and 0.12 J/mol. K, respectively. For the Y and Ho systems, respectively, the adiabatic temperature change in a 3 T field decreases at a rate of around 1.3 and 0.4 K/T. The ferro (or ferrimagnetic) to paramagnetic phase change in these two compounds, as indicated by the temperature and field dependences of the magnetothermal and magnetocaloric properties, ∆Sm and ∆Tad, is a second-order phase transition. The Arrott plots and the universal curve for YFe3 were also calculated and their features give an additional support to the second order nature of the phase transition.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

First principles and mean field study on the magnetocaloric effect of YFe3 and HoFe3 compounds

Abu-Elmagd

Hammad

Abdel-Kader

et al. 2023

Sci Rep

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“…It is really clear from the measurements that the compound displays an antiferromagnetic-paramagnetic (AFM-PM) transition in vicinity of T N =8.5 K [1]. Using Curie-Weiss law and in this way, we can make the line fit paramagnetic region of the χ −1 (T) through the following expressions [2]:…”

Section: Methods Resultsmentioning

confidence: 99%

Structural, magnetic, and magnetocaloric studies of the potassium diphosphate KCrP2O7

Elouafi¹,

Ezairi

Lmai

et al. 2023

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The structural, magnetic, and magnetocaloric characteristics of potassium diphosphate KCrP2O7 were thoroughly investigated. A solid-state reaction method has been employed to synthesize this specimen. The crystalline structure was analysed employing X-Ray Diffraction (XRD), infrared, and Raman spectroscopy at around room temperature. Detailed Rietveld refinement analysis reveals that the compound adopts a complex monoclinic structure with the space group P21/c and the lattice parameters: a = 7.357Ǻ, b = 10.011 Ǻ, and c = 8.202 Ǻ. The Magnetic measurements exhibit an antiferromagnetic-paramagnetic behavior with a second order magnetic transition near the Néel temperature TN (TN = 8.5 K) for KCrP2O7. Magnetic entropy change (-∆SM) induced by the magnetic field, was determined by employing the thermodynamic Maxwell's relation. At H=50 kOe, the (-∆S M Max ) and RCP (magnetic refrigeration capacity) near T N show a value of 4.4 J.kg-1 .K-1 and 30.06 J.kg-1, respectively for the KCrP2O7 compound.

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“…It would be informative to estimate some of the critical exponents [20,21] and compare with the MFT values. We calculated n, β, δ and ɤ parameters for DyFe3 compound, where n = 1+ ( β -1) /( β +ɤ) [22]. The parameter δ has been evaluated from the isothermal magnetization curve, where M ~H1/δ [23].…”

Section: 5-critical Exponentsmentioning

confidence: 99%

Magnetocaloric Effect in DyFe3 and GdFe3

Abu Elnasr,

Z.ElNegery,

H Aly

et al. 2024

Journal of the Egyptian Society for Basic Sciences-Physics

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In this work, we report on the calculation of the temperature dependence of Magnetic moment, total heat capacity and magnetocaloric effect (MCE) of DyFe3 and GdFe3 compounds. The calculation, using the Mean-Field Theory (MFT) of magnetization showed that both DyFe3 and GdFe3 are ferrimagnetic compounds with compensation temperatures around 509 K and 597 K, and Curie temperatures about 624K and 745K for DyFe3 and GdFe3 respectively. The maximum calculated 𝑖𝑠𝑜𝑡ℎ𝑒𝑟𝑚𝑎𝑙 𝑒𝑛𝑡𝑟𝑜𝑝𝑦 𝑐ℎ𝑎𝑛𝑔𝑒 |𝛥𝑆 𝑚 (𝑇, 𝛥𝐻)| are 0.21 and 0.19 J/mol.K and the maximum calculated 𝑎𝑑𝑖𝑎𝑏𝑎𝑡𝑖𝑐 𝑐ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝑡𝑒𝑚𝑝𝑒𝑟𝑎𝑡𝑢𝑟𝑒 |𝛥𝑇 𝑎𝑑 (𝑇, 𝛥𝐻)| are 0.92 and 0.82 K at 𝑓𝑖𝑒𝑙𝑑 𝑐ℎ𝑎𝑛𝑔𝑒 = 4 𝑇 for DyFe3 and GdFe3 respectively. The relative cooling powers RCP(S) and RCP(T), for a field change of 4T, are 4 and 3.8 J/mol and 19.5 and 24.6 K 2 for DyFe3 and GdFe3. Furthermore, the calculation of the critical exponents supports the suitability of the MFT for handling the systems under study. The type of the magnetic phase transition, at the Curie temperatures, is confirmed from the temperature dependence of the magnetization, heat capacity at different fields and MCE quantities to be a second order one.

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Magnetic Properties and the Critical Exponents in Terms of the Magnetocaloric Effect of Amorphous Fe40Ni38Mo4B18 Alloy

Cited by 12 publications

References 17 publications

First principles and mean field study on the magnetocaloric effect of YFe3 and HoFe3 compounds

First principles and mean field study on the magnetocaloric effect of YFe3 and HoFe3 compounds

Structural, magnetic, and magnetocaloric studies of the potassium diphosphate KCrP2O7

Magnetocaloric Effect in DyFe3 and GdFe3

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