Magnetothermal properties and magnetocaloric effect in transition Metal-Rich Gd-Co and Gd-Fe amorphous alloys

Elkenany, M.M.; Aly, Samy H.; Yehia, Sherif

doi:10.1016/j.cryogenics.2022.103439

Cited by 12 publications

(1 citation statement)

References 38 publications

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“…Meanwhile, the peak value of Δ S M (|Δ S M pk |) of the alloys nearly linearly depends on T C −2/3 [ 17 , 19 ]. However, in our previous work, it was found that excessive Fe replacement of Co results in a decrease in the T C and |Δ S M pk | simultaneously [ 20 ], which may be ascribed to the enhancement of antiferromagnetic Gd-Fe exchange interactions and variation in predominant exchange interactions from ferrimagnetism to sperimagnetism [ 21 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

Correlation between Magnetocaloric Properties and Magnetic Exchange Interaction in Gd54Fe36B10−xSix Amorphous Alloys

Zhang,

Tan,

Zhang

et al. 2023

Materials

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Gd54Fe36B10−xSix (x = 0, 2, 5, 8, 10) amorphous ribbons were fabricated by melt-spinning technique. Based on the molecular field theory, the magnetic exchange interaction was analyzed by constructing the two-sublattice model and deriving the exchange constants JGdGd, JGdFe and JFeFe. It was revealed that appropriate substitution content of Si for B can improve the thermal stability, maximum magnetic entropy change and widened table-like magnetocaloric effect of the alloys, while excessive Si will lead to the split of the crystallization exothermal peak, inflection-like magnetic transition and deterioration of magnetocaloric properties. These phenomena are probably correlated to the stronger atomic interaction of Fe-Si than that of Fe-B, which induced the compositional fluctuation or localized heterogeneity and then caused the different way of electron transfer and nonlinear variation in magnetic exchange constants, magnetic transition behavior and magnetocaloric performance. This work analyzes the effect of exchange interaction on magnetocaloric properties of Gd-TM amorphous alloys in detail.

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Section: Introductionmentioning

confidence: 99%

Correlation between Magnetocaloric Properties and Magnetic Exchange Interaction in Gd54Fe36B10−xSix Amorphous Alloys

Zhang,

Tan,

Zhang

et al. 2023

Materials

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The Anisotropic Magnetocaloric Effect and Size-Dependent Magnetic Properties of Iron Particles

Halool

Aly

Yehia

et al. 2022

J Supercond Nov Magn

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We present a theoretical study on the anisotropic magnetocaloric effect and the size-dependent magnetic properties of Fe particles of radii in the range 25–150 Å. An observable increase has been found in the magnetization, of the low radii (25–75 Å) particles, by reducing the temperature to 4 K. The anisotropic isothermal change in entropy ΔSm has been calculated by taking the difference between maximum ΔSm along the easy [100] and hard [111] directions. The maximum anisotropic ΔSm is 0.015 J/kg K for a field change of 500 Oe along the [100] direction. The ΔSm temperature dependence exhibits a table-like plateau for small radii (25–75 Å) and in low fields below 300Oe. This enhances the relative cooling power (RCP) of the Fe element to be 8.11 J/kg for particles of 25 Å radius. Also, the calculation of anisotropic ΔTad was performed along the easy axis and showed an increase in the maximum value around 37% relative to the experimental conventional value.

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Magnetocaloric Effect in R6Fe23: R = Dy, Ho, Er, and Tm

Elnasr

Aly

Yehia

et al. 2023

J Supercond Nov Magn

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We present a mean field study on the R6Fe23 system, where R = Dy, Ho, Er, and Tm, to calculate the magnetization, magnetic heat capacity, and the magnetocaloric effect (MCE) (isothermal entropy change (ΔSm) and the adiabatic temperature change (ΔTad)) for different field changes up to 5 T and at temperatures ranging from 0 to 600 K. The maximum ΔSm, using the trapezoidal method, for the R6Fe23 system is in the range 4.9–9.8 J/K mol, and the maximum ΔTad is in the range 9.56–15.17 K for a field change ΔH = 5 T. The largest ΔSm and largest ΔTad are found for Tm6Fe23 to be 9.8 J/K mol and 15.17 K at Curie temperature Tc = 489 K, for ΔH = 5 T. The relative cooling power RCP(S) is in the range 148–560 J/mol for ΔH = 5 T, which is comparable to that of bench-mark materials, e.g., Gd. Also, the RCP based on the adiabatic temperature change, RCP(T) is in the range 449–1092 K2 for ΔH = 5 T, which is comparable also to that of bench-mark materials, e.g., Gd. We investigated the type of phase transition in the light of universal curves, Arrott plots, and the behavior of the magnetic moment, magnetic heat capacity, and MCE (ΔSm, ΔTad), which confirm that the type of phase transition at Tc of this system is second-order phase transition (SOPT). A calculation of some critical exponents adds more evidence that the MFT is fairly suitable to handle the aforementioned properties in the studied systems.

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Magnetothermal properties and magnetocaloric effect in transition Metal-Rich Gd-Co and Gd-Fe amorphous alloys

Cited by 12 publications

References 38 publications

Correlation between Magnetocaloric Properties and Magnetic Exchange Interaction in Gd54Fe36B10−xSix Amorphous Alloys

Correlation between Magnetocaloric Properties and Magnetic Exchange Interaction in Gd54Fe36B10−xSix Amorphous Alloys

The Anisotropic Magnetocaloric Effect and Size-Dependent Magnetic Properties of Iron Particles

Magnetocaloric Effect in R6Fe23: R = Dy, Ho, Er, and Tm

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