Giant Low-Field Cryogenic Magnetocaloric Effect in a Polycrystalline EuB4O7 Compound

Yuanpeng Wang; Junsen Xiang; Lei Zhang; Jianjian Gong; Wei Li; Zhaojun Mo; Jun Shen

doi:10.1021/jacs.3c12158

Giant Low-Field Cryogenic Magnetocaloric Effect in a Polycrystalline EuB₄O₇ Compound

J Am Chem Soc. 2024 Feb 7;146(5):3315-3322. doi: 10.1021/jacs.3c12158. Epub 2024 Jan 23.

Authors

Yuanpeng Wang^{1

2}, Junsen Xiang³, Lei Zhang², Jianjian Gong^{1

2}, Wei Li⁴, Zhaojun Mo^{1

2}, Jun Shen^{1

5}

Affiliations

¹ School of Rare earths, University of Science and Technology of China, Hefei 230026, People's Republic of China.
² Key Laboratory of Rare Earths, Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341000, People's Republic of China.
³ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
⁴ CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
⁵ Department of Energy and Power Engineering, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China.

PMID: 38259107
DOI: 10.1021/jacs.3c12158

Abstract

To deal with the shortage and high price of helium-3 resources, adiabatic demagnetization refrigeration technology as an alternative to helium-3-based refrigeration technology has received much attention. The magnetism and ultralow-temperature magnetocaloric effect (MCE) of the EuB₄O₇ compound have been investigated. The results of magnetic and quasi-adiabatic demagnetization measurements suggest the absence of a magnetic order above 0.4 K for EuB₄O₇. The dipolar interaction between the nearest-neighbor Eu atoms has a characteristic energy of about 800 mK, which may induce a large MCE. The maximum magnetic entropy change reaches 22.8, 36.2, and 47.6 J·kg^-1 K^-1 at μ₀H = 0-10 kOe, 0-20 kOe, and 0-50 kOe, respectively. Measurements by a quasi-adiabatic demagnetization device show that the lowest temperature achievable (289 mK) for polycrystalline EuB₄O₇ is lower than that (362 mK) for the commercial refrigerant Gd₃Ga₅O₁₂ (GGG) single crystals. The hold time is more than 70 min below 700 mK, with an environment temperature of 2 K, proving that EuB₄O₇ exhibits superior cooling performance.