A Record-High Cryogenic Magnetocaloric Effect Discovered in EuCl<sub>2</sub> Compound
Adiabatic demagnetization refrigeration (ADR) based on the magnetocaloric effect (MCE) is a promising technique to achieve cryogenic temperature. However, magnetic entropy change (Δ<i>S</i><sub>M</sub>), the driving force of ADR, remains far below theoretical -Δ<i>S</i><sub>M</sub> = <i>nR</i>ln(2<i>J</i> + 1)/<i>M</i><sub>W</sub> for most magnetic refrigerants. Here, we report giant MCE in orthorhombic EuCl<sub>2</sub>, where a ferromagnetic ground state with excellent single-ion behavior of Eu<sup>2+</sup> and free spins has been demonstrated by combining <i>ab initio</i> calculations with Brillouin function analysis and magnetic measurements. Consequently, a record-high -Δ<i>S</i><sub>M</sub> ∼ 74.6 J·kg<sup>-1</sup>·K<sup>-1</sup> (1.8 K) at 5 T was experimentally achieved, approaching 96% of the theoretical limit (77.5 J·kg<sup>-1</sup>·K<sup>-1</sup>). At a lower field of 1 T, EuCl<sub>2</sub> also achieves the highest-ever record of -Δ<i>S</i><sub>M</sub> ∼ 36.8 J·kg<sup>-1</sup>·K<sup>-1</sup>. Further, direct quasi-adiabatic demagnetization measurements demonstrate that its large -Δ<i>S</i><sub>M</sub> allows EuCl<sub>2</sub> to maintain a long holding time at sub-Kelvin temperature (∼346 mK), surpassing all previously reported materials. These superior magnetocaloric performances position EuCl<sub>2</sub> as an attractive cryogenic refrigerant.
Authors
- Peijie Sun (ORCID: https://orcid.org/0000-0003-1504-5634)
- Jirong Sun (ORCID: https://orcid.org/0000-0003-4531-4794)
- Zhaojun Mo (ORCID: https://orcid.org/0000-0001-5183-4302)
- Fengxia Hu (ORCID: https://orcid.org/0000-0003-0383-0213)
- Baogen Shen (ORCID: https://orcid.org/0000-0003-4819-1806)
- Junsen Xiang (ORCID: https://orcid.org/0000-0002-3209-6620)
- Xin‐Yang Liu (ORCID: https://orcid.org/0000-0003-1423-605X)
- Q. Huang (ORCID: https://orcid.org/0000-0001-5135-0375)
- Yunzhong Chen (ORCID: https://orcid.org/0000-0001-8368-5823)
- Jing Wang (ORCID: https://orcid.org/0000-0001-5458-6711)
- Jian-Tao Wang (ORCID: https://orcid.org/0000-0002-0786-1212)
- Bingjie Wang (ORCID: https://orcid.org/0000-0002-0305-6267)
- Jun Shen (ORCID: https://orcid.org/0000-0001-8748-8085)
- Tongyun Zhao
Institutions
- Beijing Institute of Technology (CN)
- Chinese Academy of Sciences (CN)
- China Spallation Neutron Source (CN)
- Songshan Lake Materials Laboratory (CN)
- FZU ‒ Institute of Physics of the Academy of Sciences of the Czech Republic (CZ)
- Institute of Power Engineering (PL)
- Jiangxi Academy of Sciences (CN)
- Academy of Innovation Management (RU)
- Institute of Physics (CN)
- University of Chinese Academy of Sciences (CN)
- Ningbo Institute of Industrial Technology (CN)
- Spallation Neutron Source
- Beihang University (CN)
Publication Details
- Journal
- Journal of the American Chemical Society
- Published
- 2024-12-04
- DOI
- https://doi.org/10.1021/jacs.4c12441
- Citations
- 33
- Primary Topic
- Magnetic and transport properties of perovskites and related materials
- Type
- article
- Field-Weighted Citation Impact
- 3.89
Funders
- National Natural Science Foundation of China
- Chinese Academy of Sciences
- National Key Research and Development Program of China