An indirect approach based on Clausius–Clapeyron equation to determine entropy change for the first-order magnetocaloric materials

Kuangdi, Xu; Li, Zhe; Zhang, Yuanlei; Jing, Chao

doi:10.1016/j.physleta.2015.10.029

Cited by 37 publications

(17 citation statements)

References 38 publications

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“…7). This value is significantly higher than those in other MM ’ X compounds1215373839 and is comparable to some giant magnetocaloric materials with FOMST4041. The enhanced Δ S T can be ascribed to the extremely narrow transition temperature width and the improved FM exchange interaction activated by the introduction of more Fe atom6.…”

Section: Resultsmentioning

confidence: 64%

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Magnetocaloric effect and negative thermal expansion in hexagonal Fe doped MnNiGe compounds with a magnetoelastic AFM-FM-like transition

Kuangdi

Liu

et al. 2017

Sci Rep

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We report a detailed study of two successive first-order transitions, including a martensitic transition (MT) and an antiferromagnetic (AFM)-ferromagnetic (FM)-like transition, in Mn1-xFexNiGe (x = 0, 0.06, 0.11) alloys by X-ray diffraction, differential scanning calorimetry, magnetization and linear thermal expansion measurements. Such an AFM-FM-like transition occurring in the martensitic state has seldom been observed in the M(T) curves. The results of Arrott plot and linear relationship of the critical temperature with M2 provide explicit evidence of its first-order magnetoelastic nature. On the other hand, their performances as magnetocaloric and negative thermal expansion materials were characterized. The isothermal entropy change for a field change of 30 kOe reaches an impressive value of −25.8 J/kg K at 203 K for x = 0.11 compared to the other two samples. It demonstrates that the magneto-responsive ability has been significantly promoted since an appropriate amount of Fe doping can break the local Ni-6Mn AFM configuration. Moreover, the Fe-doped samples reveal both the giant negative thermal expansion and near-zero thermal expansion for different temperature ranges. For instance, the average thermal expansion coefficient ā of x = 0.06 reaches −60.7 × 10−6/K over T = 231–338 K and 0.6 × 10−6/K over T = 175–231 K during cooling.

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Section: Resultsmentioning

confidence: 64%

“…Δ S T associated with the FOMST was calculated by means of the integrated Maxwell relation using M(T ) data to avoid the “spurious” spike3637,…”

Section: Resultsmentioning

confidence: 99%

Magnetocaloric effect and negative thermal expansion in hexagonal Fe doped MnNiGe compounds with a magnetoelastic AFM-FM-like transition

Kuangdi

Liu

et al. 2017

Sci Rep

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“…Good agreement was obtained between these two. Alternatively to the Maxwell relation, the isothermal entropy change can be calculated using the Clausius-Clapeyron equation, which essentially leads to the same results as also shown for the magnetocaloric effect [53]. The Clausius-Clapeyron equation for elastocaloric material can be written as follows:…”

Section: Indirect Methodsmentioning

confidence: 96%

Understanding the Thermodynamic Properties of the Elastocaloric Effect Through Experimentation and Modelling

Tušek

Engelbrecht

Mañosa

et al. 2016

Shap. Mem. Superelasticity

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This paper presents direct and indirect methods for studying the elastocaloric effect (eCE) in shape memory materials and its comparison. The eCE can be characterized by the adiabatic temperature change or the isothermal entropy change (both as a function of applied stress/strain). To get these quantities, the evaluation of the eCE can be done using either direct methods, where one measures (adiabatic) temperature changes or indirect methods where one can measure the stress-strain-temperature characteristics of the materials and from these deduce the adiabatic temperature and isothermal entropy changes. The former can be done using the basic thermodynamic relations, i.e. Maxwell relation and Clausius-Clapeyron equation. This paper further presents basic thermodynamic properties of shape memory materials, such as the adiabatic temperature change, isothermal entropy change and total entropy-temperature diagrams (all as a function of temperature and applied stress/strain) of two groups of materials (Ni-Ti and Cu-Zn-Al alloys) obtained using indirect methods through phenomenological modelling and Maxwell relation. In the last part of the paper, the basic definition of the efficiency of the elastocaloric thermodynamic cycle (coefficient of performance) is defined and discussed.

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“…4. In order to avoid the mixed phases disturbing the final results, the isothermal entropy change ∆S T during reverse MPT under various magnetic fields was calculated from the M-T curves (see inset of this figure) based on the Maxwell relation as given below, 23,24 Fig. 4, we found that the peak of ∆S T with the maximum of about 2.0 J/Kg K appears nearby the A s during the inverse MPT for Ni 50 Mn 34 Pd 4 Sn 12 at which the magnetization changes dramatically.…”

Section: Resultsmentioning

confidence: 99%

The effect of Pd on martensitic transformation and magnetic properties for Ni50Mn38−xPdxSn12Heusler alloys

Jing

Zheng

et al. 2016

AIP Advances

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In the past decade, Mn rich Ni-Mn based alloys have attained considerable attention due to their abundant physics and potential application as multifunctional materials. In this paper, polycrystalline Ni50Mn38−xPdxSn12 (x = 0, 2, 4, 6) Heusler alloys have been prepared, and the martensitic phase transformation (MPT) together with the shape memory effect and the magnetocaloric effect has been investigated. The experimental result indicates that the MPT evidently shifts to a lower temperature with increase of Pd substitution for Mn atoms, which can be attributed to the weakness of the hybridization between the Ni atom and excess Mn on the Sn site rather than the electron concentration. The physics properties study focused on the sample of Ni50Mn34Pd4Sn12 shows a good two-way shape memory behavior, and the maximum value of strain Δ L/L reaches about 0.13% during the MPT. The small of both entropy change Δ ST and magnetostrain can be ascribed to the inconspicuous influence of magnetic field induced MPT.

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An indirect approach based on Clausius–Clapeyron equation to determine entropy change for the first-order magnetocaloric materials

Cited by 37 publications

References 38 publications

Magnetocaloric effect and negative thermal expansion in hexagonal Fe doped MnNiGe compounds with a magnetoelastic AFM-FM-like transition

Magnetocaloric effect and negative thermal expansion in hexagonal Fe doped MnNiGe compounds with a magnetoelastic AFM-FM-like transition

Understanding the Thermodynamic Properties of the Elastocaloric Effect Through Experimentation and Modelling

The effect of Pd on martensitic transformation and magnetic properties for Ni50Mn38−xPdxSn12Heusler alloys

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