Investigation of the critical behavior and magnetocaloric properties in the nanocrystalline CuNi powders

Alleg, S.; Souilah, S.; Dadda, K.; Suñol, J.J.; Hlil, E.K.; Lassri, H.

doi:10.1016/j.jmmm.2017.08.010

Cited by 11 publications

(3 citation statements)

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“…The values of critical exponents of various models and that of Fe‐ and Ni‐based alloys are summarized in Table 1 . Alleg et al [ 25 ] showed that the mechanically alloyed Ni 50 Cu 50 was close to the mean‐field model suggesting long‐range interaction around the Curie temperature. On the other hand, Repaka et al [ 21 ] reported that mechanically alloyed Fe 30 Cu 70 supports the 3D‐Heisenberg model.…”

Section: Resultsmentioning

confidence: 81%

“…[ 20–24 ] On the other hand, few other Fe‐ and Ni‐based alloys, including NiCu system, show critical exponents that deviate from the theory with a β value in the range of 0.33–0.60. [ 25–28 ] The Fe‐substituted NiV system shows a complex magnetic structure where the critical exponents do not follow any theoretical model. [ 9 ] The critical exponents values are also influenced by the cluster formation.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Curie Temperature and Critical Exponents of Fe‐Substituted NiCu Alloy

Jacob

Joseyphus

2021

Physica Status Solidi (a)

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The magnetic moment and the Curie temperature of the NiCu alloy decrease to a large extent with Cu. A Ni60Cu40 alloy with Fe substitutions up to 2 at% using a polyol‐mediated synthesis process resulting in enhanced magnetic properties is obtained. The Ni60Cu39Fe1 and Ni60Cu38Fe2 alloys show fcc phase with the Curie temperatures of 237 and 266 K, respectively. The room temperature magnetization measurement shows paramagnetic behavior, whereas, at 15 K, the 1 at% Fe‐substituted alloy exhibits a saturation magnetization of 20 emu g−1 that increases by 25% with 2 at% Fe. The positive slope in the Arrott plot confirms the second‐order phase transition in the alloys. The maximum magnetic entropy change (MCE) is observed as 0.101 J kg−1 K−1 for the Ni60Cu39Fe1 alloy with the peak temperature of 238 K in an applied magnetic field of 0.5 T. The critical exponent (β) calculated using the MCE method is in the range of 0.576(3)–0.587(3) for the alloys, whereas the values obtained using the Kouvel‐Fisher (KF) method are 0.523(3)–0.565(2). The extracted β values are slightly greater than the mean‐field model suggesting clustering behavior in the alloys.

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Section: Resultsmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Enhanced Curie Temperature and Critical Exponents of Fe‐Substituted NiCu Alloy

Jacob

Joseyphus

2021

Physica Status Solidi (a)

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“…Many methods have been used to produce magnetocaloric materials such as mechanical alloying (MA) [19,20], solid state reactions [21], sol gel routes [22], melt spinning [23,24], etc. In the mechanically alloyed powders, the MCE response can be affected by several factors such as the alloy composition, the multiphase character, the demagnetizing field effect, etc.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Critical Behavior, Magnetocaloric Effect and Hyperfine Structure in the Fe72Nb8B20 Powders

et al. 2020

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Microstructure as well as magnetic, thermal and magnetocaloric properties of the mechanically alloyed Fe72Nb8B20 powders have been investigated by means of Mössbauer spectrometry, differential scanning calorimetry (DSC), and magnetic measurements. The Mössbauer spectrometry results showed the formation of nanostructured Fe(B) and Fe(Nb) solid solutions, Fe2B boride, and an amorphous phase. The endothermic and exothermic peaks that are observed in the DSC curves might be related to the Curie temperature, and the crystallization of the amorphous phase, respectively. The critical exponent values around the magnetic phase transition of the amorphous phase (TC = 480 K), are deduced from the modified Arrott plots, Kouvel−Fisher curves and critical isotherm examination. The calculated values (β = 0.457 ± 0.012, γ = 0.863 ± 0.136 and δ = 3.090 ± 0.004) are near to those of the mean field model, revealing a dominating role of magnetic order arising due to long-range ferromagnetic interactions, as the critical exponents are mean-field-like. The maximum entropy change and the refrigerant capacity values are 1.45 J/kg·K and 239 J/kg, respectively, under a magnetic field of 5 T.

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