Structural dynamics of first-order phase transition in giant magnetocaloric La(Fe,Si)13: The free energy landscape

André Azevedo Beleza; Bernardo Pires; Rafael Almeida; John S.O. Evans; António M. dos Santos; Mathias Frontzek; Edmund Lovell; Benedikt Beckmann; Konstantin Skokov; Oliver Gutfleisch; João Pedro Araujo; A. M. Milinda Abeykoon; João S Amaral; João Horta Belo

doi:10.1016/j.mtphys.2024.101388

Structural dynamics of first-order phase transition in giant magnetocaloric La(Fe,Si)₁₃: The free energy landscape

André Azevedo Beleza, Bernardo Pires, Rafael Almeida, John S.O. Evans, António M. dos Santos, Mathias Frontzek, Edmund Lovell, Benedikt Beckmann, Konstantin Skokov, Oliver Gutfleisch, João Pedro Araujo, A. M. Milinda Abeykoon, João S Amaral, João Horta Belo

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

Abstract

Maximizing the performance of magnetic refrigerators and thermomagnetic energy harvesters is imperative for their successful implementation and can be done by maximizing their operation frequency. One of the features delimiting the frequency and efficiency of such devices is the phase transition kinetics of their magnetocaloric/thermomagnetic active material. While previous studies have described the magnetic component governing the kinetics of the magnetovolume phase transition in La(Fe,Si)₁₃ giant magnetocaloric materials, a comprehensive description of its structural component has yet to be explored. In this study, in situ synchrotron X-ray diffraction is employed to describe the structural changes upon magnetic field application/removal. Long magnetic field dependent relaxation times up to a few hundred seconds are observed after the driving field is paused. The phase transition is found to be highly asymmetric upon magnetic field cycling due to the different Gibbs energy landscapes and the absence of an energy barrier upon field removal. An exponential relationship is found between the energy barriers and the relaxation times, suggesting the process is governed by a non-thermal activation over an energy barrier process. Such fundamental knowledge on first-order phase transition kinetics suggests pathways for materials optimization and smarter design of magnetic field cycling in real-life devices.

Original language	English
Article number	101388
Journal	Materials Today Physics
Volume	42
DOIs	https://doi.org/10.1016/j.mtphys.2024.101388
State	Published - Mar 2024

Funding

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Joao H. Belo reports financial support was provided by Fulbright Portugal. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.Work partially supported by the projects PTDC/EMETED/3099/2020, UIDP/04968/2020-Programático (https://doi.org/10.54499/UIDP/04968/2020), UIDB/04968/2020 (https://doi.org/10.54499/UIDB/04968/2020" id="intref0030b), LA/P/0095/2020 (https://doi.org/10.54499/LA/P/0095/2020), NECL-NORTE-010145-FEDER-022096, CERN/FISTEC/0003/2019 and the bilateral research fund grant SMARTX from Fundação para a Ciência e Tecnologia (FCT) and from and the Portuguese Association of Researchers and Student in the UK (PARSUK), Portugal, and within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC). J.H. Belo also deeply acknowledges Fullbright Portugal for his Fulbright Visiting Scholar grant, and FCT for his contract DL57/2016, with reference SFRH-BPD-87430/2012, and DL57/2016/CP1454/CT0013, with reference 10.54499/DL57/2016/CP1454/CT0013, DOI: 10.54499/DL57/2016/CP1454/CT0013. R. Almeida acknowledges FCT for the PhD grant with reference 2022.13354.BD. A portion of this research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. We acknowledge financial support by the Deutsche Forschungsgemeinschaft (DFG) within the CRC/TRR 270 (Project-ID 405553726).

Funders	Funder number
Fulbright Portugal	PTDC/EMETED/3099/2020

Access to Document

10.1016/j.mtphys.2024.101388

Cite this

Beleza, A. A., Pires, B., Almeida, R., Evans, J. S. O., dos Santos, A. M., Frontzek, M., Lovell, E., Beckmann, B., Skokov, K., Gutfleisch, O., Araujo, J. P., Milinda Abeykoon, A. M., S Amaral, J., & Belo, J. H. (2024). Structural dynamics of first-order phase transition in giant magnetocaloric La(Fe,Si)₁₃: The free energy landscape. Materials Today Physics, 42, Article 101388. https://doi.org/10.1016/j.mtphys.2024.101388

@article{049bea24e4c34be08e0a6742b0538178,

title = "Structural dynamics of first-order phase transition in giant magnetocaloric La(Fe,Si)13: The free energy landscape",

abstract = "Maximizing the performance of magnetic refrigerators and thermomagnetic energy harvesters is imperative for their successful implementation and can be done by maximizing their operation frequency. One of the features delimiting the frequency and efficiency of such devices is the phase transition kinetics of their magnetocaloric/thermomagnetic active material. While previous studies have described the magnetic component governing the kinetics of the magnetovolume phase transition in La(Fe,Si)13 giant magnetocaloric materials, a comprehensive description of its structural component has yet to be explored. In this study, in situ synchrotron X-ray diffraction is employed to describe the structural changes upon magnetic field application/removal. Long magnetic field dependent relaxation times up to a few hundred seconds are observed after the driving field is paused. The phase transition is found to be highly asymmetric upon magnetic field cycling due to the different Gibbs energy landscapes and the absence of an energy barrier upon field removal. An exponential relationship is found between the energy barriers and the relaxation times, suggesting the process is governed by a non-thermal activation over an energy barrier process. Such fundamental knowledge on first-order phase transition kinetics suggests pathways for materials optimization and smarter design of magnetic field cycling in real-life devices.",

author = "Beleza, {Andr{\'e} Azevedo} and Bernardo Pires and Rafael Almeida and Evans, {John S.O.} and {dos Santos}, {Ant{\'o}nio M.} and Mathias Frontzek and Edmund Lovell and Benedikt Beckmann and Konstantin Skokov and Oliver Gutfleisch and Araujo, {Jo{\~a}o Pedro} and {Milinda Abeykoon}, {A. M.} and {S Amaral}, Jo{\~a}o and Belo, {Jo{\~a}o Horta}",

note = "Publisher Copyright: {\textcopyright} 2024",

year = "2024",

month = mar,

doi = "10.1016/j.mtphys.2024.101388",

language = "English",

volume = "42",

journal = "Materials Today Physics",

issn = "2542-5293",

publisher = "Elsevier",

}

Beleza, AA, Pires, B, Almeida, R, Evans, JSO, dos Santos, AM , Frontzek, M, Lovell, E, Beckmann, B, Skokov, K, Gutfleisch, O, Araujo, JP, Milinda Abeykoon, AM, S Amaral, J & Belo, JH 2024, 'Structural dynamics of first-order phase transition in giant magnetocaloric La(Fe,Si)₁₃: The free energy landscape', Materials Today Physics, vol. 42, 101388. https://doi.org/10.1016/j.mtphys.2024.101388

TY - JOUR

T1 - Structural dynamics of first-order phase transition in giant magnetocaloric La(Fe,Si)13

T2 - The free energy landscape

AU - Beleza, André Azevedo

AU - Pires, Bernardo

AU - Almeida, Rafael

AU - Evans, John S.O.

AU - dos Santos, António M.

AU - Frontzek, Mathias

AU - Lovell, Edmund

AU - Beckmann, Benedikt

AU - Skokov, Konstantin

AU - Gutfleisch, Oliver

AU - Araujo, João Pedro

AU - Milinda Abeykoon, A. M.

AU - S Amaral, João

AU - Belo, João Horta

PY - 2024/3

Y1 - 2024/3

N2 - Maximizing the performance of magnetic refrigerators and thermomagnetic energy harvesters is imperative for their successful implementation and can be done by maximizing their operation frequency. One of the features delimiting the frequency and efficiency of such devices is the phase transition kinetics of their magnetocaloric/thermomagnetic active material. While previous studies have described the magnetic component governing the kinetics of the magnetovolume phase transition in La(Fe,Si)13 giant magnetocaloric materials, a comprehensive description of its structural component has yet to be explored. In this study, in situ synchrotron X-ray diffraction is employed to describe the structural changes upon magnetic field application/removal. Long magnetic field dependent relaxation times up to a few hundred seconds are observed after the driving field is paused. The phase transition is found to be highly asymmetric upon magnetic field cycling due to the different Gibbs energy landscapes and the absence of an energy barrier upon field removal. An exponential relationship is found between the energy barriers and the relaxation times, suggesting the process is governed by a non-thermal activation over an energy barrier process. Such fundamental knowledge on first-order phase transition kinetics suggests pathways for materials optimization and smarter design of magnetic field cycling in real-life devices.

AB - Maximizing the performance of magnetic refrigerators and thermomagnetic energy harvesters is imperative for their successful implementation and can be done by maximizing their operation frequency. One of the features delimiting the frequency and efficiency of such devices is the phase transition kinetics of their magnetocaloric/thermomagnetic active material. While previous studies have described the magnetic component governing the kinetics of the magnetovolume phase transition in La(Fe,Si)13 giant magnetocaloric materials, a comprehensive description of its structural component has yet to be explored. In this study, in situ synchrotron X-ray diffraction is employed to describe the structural changes upon magnetic field application/removal. Long magnetic field dependent relaxation times up to a few hundred seconds are observed after the driving field is paused. The phase transition is found to be highly asymmetric upon magnetic field cycling due to the different Gibbs energy landscapes and the absence of an energy barrier upon field removal. An exponential relationship is found between the energy barriers and the relaxation times, suggesting the process is governed by a non-thermal activation over an energy barrier process. Such fundamental knowledge on first-order phase transition kinetics suggests pathways for materials optimization and smarter design of magnetic field cycling in real-life devices.

UR - http://www.scopus.com/inward/record.url?scp=85187206591&partnerID=8YFLogxK

U2 - 10.1016/j.mtphys.2024.101388

DO - 10.1016/j.mtphys.2024.101388

M3 - Article

AN - SCOPUS:85187206591

SN - 2542-5293

VL - 42

JO - Materials Today Physics

JF - Materials Today Physics

M1 - 101388

ER -

Structural dynamics of first-order phase transition in giant magnetocaloric La(Fe,Si)₁₃: The free energy landscape

Abstract

Funding

Access to Document

Other files and links

Fingerprint

Cite this