“Two-steps” process in the first-order transformation of giant magnetocaloric materials

Hardy, V.; Hamane, Radia; Veillon, Fabien; Risser, Michel; Guillou, F.

doi:10.1016/j.actamat.2022.117869

Cited by 9 publications

(6 citation statements)

References 35 publications

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“…The total Gibbs free energy of a solid phase transformation system (e.g. the martensitic alloy) encompasses contributions from chemical, elastic, and interfacial energy [38]. During the cooling process, the chemical energy by undercooling predominates in the first stage of the martensitic transformation.…”

Section: Resultsmentioning

confidence: 99%

“…Meanwhile, the refined HRTEM image and its corresponding ε xx strain distribution by geometric phase analysis in figures 3(c) and (d) show the nano-scale (<20 nm) local strains in the austenite, demonstrating there exist the randomly distributed local stresses caused by defects. Both the longrange restrictive internal stress and the random local stresses tend to stabilize the untransformed austenite and prevents it from further transforming into martensite, and thus its corresponding transformation temperature is shifted to much lower temperature [38]. Figures 3(g) and (h) further show that the phase boundary region (middle) between the austenite (left) and the tetragonal NM (right) is not a very sharp habit plane but a wide area of about 80 nm with defects induced inhomogeneous strain distribution inside.…”

Section: Resultsmentioning

confidence: 99%

“…The precipitate is a non-transforming phase that introduces additional interfaces in the alloy, thereby increasing the interfacial energy hindrance. Meanwhile, the lattice distortion surrounding the precipitate increases the elastic energy hindrance [34,38]. Consequently, the propagation of martensite is restrained to some extend when encountering the precipitates.…”

Section: Resultsmentioning

confidence: 99%

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Two magnetic entropy peaks during one-step martensitic transformation in a Ni₄₂Co₈Mn_37.5In_12.5 alloy

Cheng

Wang

et al. 2023

J. Phys. D: Appl. Phys.

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Magnetic shape memory alloys with multiple entropy change (ΔSM) peaks are promising to extend the working temperature window (ΔTeff) in active magnetic refrigeration. They usually have multi-step martensitic transformations, since the multiple variations of structure and magnetic states lead to the one-to-one corresponding ΔSM peaks. In this work, we report an interesting Ni42Co8Mn37.5In12.5 magnetocaloric alloy, which exhibits only one-step martensitic transformation but generates two considerable ΔSM peaks with the value of 7.2 J·K-1·kg-1 and 9.9 J·K-1·kg-1 under 6 T respectively. This phenomenon is attributed to the restriction internal stresses stemming from the lattice mismatch between martensite and austenite, the random local stresses produced by defects, the interfacial hindrances of wide phase boundaries, and the inhibition of dispersed precipitates, which divide the one-step transformation into two discrete stages. Such multiple ΔSM peaks are beneficial for expanding the working temperature window of magnetocaloric refrigerators.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Two magnetic entropy peaks during one-step martensitic transformation in a Ni₄₂Co₈Mn_37.5In_12.5 alloy

Cheng

Wang

et al. 2023

J. Phys. D: Appl. Phys.

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“…They explained the na-ture of the observed behavior from atomistic scale experiments (X-ray absorption spectroscopy (XAS), XMCD, and Mössbauer spectroscopy) together with first-principles calculations. Hardy et al [179] proposed a simple thermodynamic model to describe the transition dynamics of this two-step process in the LaFe 13-x Si x system by considering a Gibbs free energy of the mixed state including three terms: chemical, elastic, and interfacial. In addition to these physical insights, various optimization methods toward performance improvement and microstructure modification have been implemented.…”

Section: Me Coupled La(fesi) 13 Based Compoundsmentioning

confidence: 99%

Advanced Magnetocaloric Materials for Energy Conversion: Recent Progress, Opportunities, and Perspective

Zhang,

Miao,

van Dijk

et al. 2024

Advanced Energy Materials

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Solid‐state caloric effects as intrinsic thermal responses to different physical external stimuli (magnetic‐, uniaxial stress‐, pressure‐, and electric‐fields) can achieve a higher energy efficiency compared with traditional gas compression techniques. Among these effects, magnetocaloric energy conversion is regarded as the best available alternative and has been exploited extensively for promising application scenarios in the last decades. This review systematically introduces the magnetocaloric effect and its applications, and summarizes the corresponding representative magnetocaloric materials, as well as important progress in recent years. Specifically, the review focuses on some key understandings of the magnetocaloric effect by utilizing state‐of‐the‐art technical tools such as synchrotron X‐ray, neutron scattering, muon spin spectroscopy, positron annihilation spectroscopy, high magnetic fields, etc., and highlights their importance toward advanced materials design and development. An overview of the basic principles and applications of these advanced techniques on magnetocaloric materials is provided. Finally, the challenges and perspectives on further developments in this field are discussed. Further in‐depth understanding and manufacturing technology advancement combined with fast‐developed artificial intelligence and machine learning are expected to advance the magnetocaloric energy conversion technology closer to real applications.

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“…Cooling by adiabatic demagnetization refrigerators (ADRs) relies on the magnetocaloric effect, which describes the entropy change associated with the temperature and the magnitude of applied fields. − Practical devices were first proposed by Giauque and Macdougall in 1933, by which cooling from 3.5 to 0.5 K was realized in a one-shot mode . The constant low temperature was not maintained on ADRs until 1954, when successive cycles of magnetization were performed on a device constructed by Heer, Barnes, and Daunt .…”

Section: Introductionmentioning

confidence: 99%

Strong Magnetocaloric Coupling in Oxyorthosilicate with Dense Gd³⁺ Spins

Yang

Zhang

et al. 2023

Inorg. Chem.

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Searching for working refrigerant materials is the key element in the design of magnetic cooling devices. Herein, we report on the thermodynamic and magnetocaloric parameters of an X 1 phase oxyorthosilicate, Gd2SiO5, by field-dependent static magnetization and specific heat measurements. An overall correlation strength of |J|S 2 ≈ 3.4 K is derived via the mean-field estimate, with antiferromagnetic correlations between the ferromagnetically coupled Gd–Gd layers. The magnetic entropy change −ΔS m is quite impressive, reaches 0.40 J K–1 cm–3 (58.5 J K–1 kg–1) at T = 2.7 K, with the largest adiabatic temperature change T ad = 23.2 K for a field change of 8.9 T. At T = 20 K, the lattice entropy S L is small enough compared to the magnetic entropy S m, S m/S L = 21.3, which warrants its potential in 2 −20 K cryocoolers with both the Stirling and Carnot cycles. Though with relatively large exchange interactions, the layered A-type spin arrangement ultimately enhances the magnetocaloric coupling, raising the possibilities of designing magnetic refrigerants with a high ratio of cooling capacity to volume.

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“Two-steps” process in the first-order transformation of giant magnetocaloric materials

Cited by 9 publications

References 35 publications

Two magnetic entropy peaks during one-step martensitic transformation in a Ni₄₂Co₈Mn_37.5In_12.5 alloy

Two magnetic entropy peaks during one-step martensitic transformation in a Ni₄₂Co₈Mn_37.5In_12.5 alloy

Advanced Magnetocaloric Materials for Energy Conversion: Recent Progress, Opportunities, and Perspective

Strong Magnetocaloric Coupling in Oxyorthosilicate with Dense Gd³⁺ Spins

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“Two-steps” process in the first-order transformation of giant magnetocaloric materials

Cited by 9 publications

References 35 publications

Two magnetic entropy peaks during one-step martensitic transformation in a Ni42Co8Mn37.5In12.5 alloy

Two magnetic entropy peaks during one-step martensitic transformation in a Ni42Co8Mn37.5In12.5 alloy

Advanced Magnetocaloric Materials for Energy Conversion: Recent Progress, Opportunities, and Perspective

Strong Magnetocaloric Coupling in Oxyorthosilicate with Dense Gd3+ Spins

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Two magnetic entropy peaks during one-step martensitic transformation in a Ni₄₂Co₈Mn_37.5In_12.5 alloy

Two magnetic entropy peaks during one-step martensitic transformation in a Ni₄₂Co₈Mn_37.5In_12.5 alloy

Strong Magnetocaloric Coupling in Oxyorthosilicate with Dense Gd³⁺ Spins