Large magnetic entropy change in a Heusler alloy<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ni</mml:mi></mml:mrow><mml:mrow><mml:mn>52.6</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Mn</mml:mi></mml:mrow><mml:mrow><mml:mn>23.1</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ga</mml:mi></mml:mrow><mml:mrow><mml:mn>

Hu, Fengxia; Shen, Baogen; Sun, J. R.; Wu, Guangheng

doi:10.1103/physrevb.64.132412

Cited by 256 publications

(141 citation statements)

References 30 publications

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“…Other promising materials are lanthanum perovskite manganites, Heusler alloys, MnAs-based compounds, La(Fe,Si) 13 -type alloys, etc. [11][12][13].…”

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confidence: 99%

Inverse magnetocaloric effect in sol–gel derived nanosized cobalt ferrite

et al. 2010

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The magnetocaloric properties of cobalt ferrite nanoparticles were investigated to evaluate the potential of these materials as magnetic refrigerants. Nanosized cobalt ferrites were synthesized by the method of sol-gel combustion. The nanoparticles were found to be spherical with an average crystallite size of 14 nm. The magnetic entropy change ( S m ) calculated indirectly from magnetization isotherms in the temperature region 170-320 K was found to be negative, signifying an inverse magnetocaloric effect in the nanoparticles. The magnitudes of the S m values were found to be larger when compared to the reported values in the literature for the corresponding ferrite materials in the nanoregime.

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“…Other promising materials are lanthanum perovskite manganites, Heusler alloys, MnAs-based compounds, La(Fe,Si) 13 -type alloys, etc. [11][12][13].…”

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confidence: 99%

Inverse magnetocaloric effect in sol–gel derived nanosized cobalt ferrite

et al. 2010

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“…[40,41] The decreasing slope of T M with e/a varies depending on the specific Z element in NiMnZ. In another our work, [12] T M was successfully tuned to room temperature through adjusting the Ni:Mn:Ga ratio to change e/a, and a large negative entropy change was observed in single crystal Ni 52.6 Mn 23.1 Ga 24.3 . Figure 4 displays the isothermal M-H curves measured at different temperatures with a magnetic field along the [001] direction of the martensitic state.…”

Section: Magnetic Entropy Change In Conventional Nimn-based Heusler Amentioning

confidence: 69%

“…The origin of the large ∆S in Ni 51.5 Mn 22.7 Ga 25.8 is attributable to the considerable magnetization jump caused by the change of the magnetocrystalline anisotropy due to the martensiticaustenitic structure transition. Furthermore, we find that the thermal hysteresis is ∼ 10 K for Ni 51 The inset displays the detailed M-H curves at 297 K and 310 K. [12] Note that the martensitic transition temperature, T M ∼ 197 K, of Ni 51.5 Mn 22.7 Ga 25.8 polycrystalline is still far below the room temperature. A general rule based on NiMnZ (Z=Sn, In, Al, Ga) ternary alloys shows that T M sharply decreases while T C of the parent phase remains nearly unchanged with decreasing valence electron concentration e/a.…”

Section: Magnetic Entropy Change In Conventional Nimn-based Heusler Amentioning

confidence: 78%

“…[44,45] For the present sample, due to the possibility of two-phase coexistence, two abrupt decreases of magnetization take place with increasing temperature. The combined result makes the saturated magnetization of the martensitic state at low temperature 297 K 45% higher than that of the austenitic state at high temperature 310 K for single crystal Ni [12] 037505-3…”

Section: Magnetic Entropy Change In Conventional Nimn-based Heusler Amentioning

confidence: 99%

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Magnetic entropy change involving martensitic transition in NiMn-based Heusler alloys

Hu¹,

Shen²,

Sun³

2013

Chinese Phys. B

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Our recent progress on magnetic entropy change (∆S) involving martensitic transition in both conventional and metamagnetic NiMn-based Heusler alloys is reviewed. For the conventional alloys, where both martensite and austenite exhibit ferromagnetic (FM) behavior but show different magnetic anisotropies, a positive ∆S as large as 4.1 J·kg −1 ·K −1 under a field change of 0-0.9 T was first observed at martensitic transition temperature T M ∼ 197 K. Through adjusting the Ni:Mn:Ga ratio to affect valence electron concentration e/a, T M was successfully tuned to room temperature, and a large negative ∆S was observed in a single crystal. The −∆S attained 18.0 J·kg −1 ·K −1 under a field change of 0-5 T. We also focused on the metamagnetic alloys that show mechanisms different from the conventional ones. It was found that post-annealing in suitable conditions or introducing interstitial H atoms can shift the T M across a wide temperature range while retaining the strong metamagnetic behavior, and hence, retaining large magnetocaloric effect (MCE) and magnetoresistance (MR). The melt-spun technique can disorder atoms and make the ribbons display a B2 structure, but the metamagnetic behavior, as well as the MCE, becomes weak due to the enhanced saturated magnetization of martensites. We also studied the effect of Fe/Co co-doping in Ni 45 (Co 1−x Fe x ) 5 Mn 36.6 In 13.4 metamagnetic alloys. Introduction of Fe atoms can assist the conversion of the Mn-Mn coupling from antiferromagnetic to ferromagnetic, thus maintaining the strong metamagnetic behavior and large MCE and MR. Furthermore, a small thermal hysteresis but significant magnetic hysteresis was observed around T M in Ni 51 Mn 49−x In x metamagnetic systems, which must be related to different nucleation mechanisms of structural transition under different external perturbations.

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“…Nonetheless, the Curie temperature of Gd 5 Si 2 Ge 2 is about 276 K, which is much lower than that of Gd of 294 K, making this alloy difficult to be used in room-temperature magnetic refrigerators [11]. For this reason, there is an extensive search of new materials suited for solid-state cooling machines working in this temperature range, such as Ni-Mn-Ga alloys [12], Mn-As-Sb alloys [13], La-Fe-Co-S alloys [14], Mn-Fe-P-As alloys [15] and various compounds of manganites [5].…”

Section: Introductionmentioning

confidence: 99%

Magnetic and Magnetocaloric Properties of La0.67Pb0.33−x Ag x MnO3 Compounds

Mtiraoui

Dhahri

Oumezine

et al. 2012

J Supercond Nov Magn

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In this paper, we have studied the magnetic and magnetocaloric properties of the perovskite manganites La 0.67 Pb 0.33−x Ag x MnO 3 (0 ≤ x ≤ 0.15), which show a sharp paramagnetic-ferromagnetic phase transition over a wide temperature range (T = 250-401 K). The Curie temperature has been analyzed by two methods: using the numerical derivative dM/dT and the thermodynamic model. The experimental results indicate that T C decreases from 368 to 288 K with increasing Ag substitution independently of the method used to obtain T C . Upon 10 KOe applied magnetic field, the large magnetic-entropy change (| S M |) reaches values of 2.75, 3, 3.25 and 3.5 J/kg K for x = 0, 0.05, 0.10 and 0.15 compositions, respectively, which are comparable to that of Gd. The relative cooling power (RCP) increases with increasing Ag content from 68.75 (x = 0) to 156.27 J/kg (x = 0.15) for H = 10 KOe. Through these results, La 0.67 Pb 0.33−x Ag x MnO 3 materials are strongly suggested for the use of active refrigerants for magnetic refrigeration technology near room temperature.N. Mtiraoui ( ) · M. Oumezine

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Large magnetic entropy change in a Heusler alloyNi52.6Mn23.1Ga

Cited by 256 publications

References 30 publications

Inverse magnetocaloric effect in sol–gel derived nanosized cobalt ferrite

Inverse magnetocaloric effect in sol–gel derived nanosized cobalt ferrite

Magnetic entropy change involving martensitic transition in NiMn-based Heusler alloys

Magnetic and Magnetocaloric Properties of La0.67Pb0.33−x Ag x MnO3 Compounds

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