中国物理B ›› 2026, Vol. 35 ›› Issue (7): 77505-077505.doi: 10.1088/1674-1056/ae360a

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Enhanced low-field magnetocaloric effect induced by Co doping in RCu2-xCox (R = Er, Ho) compounds for liquid hydrogen

Lu Tian(田路)1, Zhaojun Mo(莫兆军)1,†, Xuanyu Qiao(乔轩雨)1, Chenyang Ma(马辰洋)2, and Guodong Liu(刘国栋)2   

  1. 1 Key Laboratory of Rare Earths, Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341000, China;
    2 School of Science, Hebei University of Technology, Tianjin 300130, China
  • 收稿日期:2025-11-21 修回日期:2026-01-06 接受日期:2026-01-09 发布日期:2026-07-21
  • 通讯作者: Zhaojun Mo E-mail:mozhaojun@gia.cas.cn
  • 基金资助:
    This work was supported by the Light of the Soviet Area Innovation Leading Talent Program (Grant No. E23HB00101), the National Natural Science Foundation of China (Grant No. 52501262), and the Key Laboratory of Rare Earths, Chinese Academy of Sciences.

Enhanced low-field magnetocaloric effect induced by Co doping in RCu2-xCox (R = Er, Ho) compounds for liquid hydrogen

Lu Tian(田路)1, Zhaojun Mo(莫兆军)1,†, Xuanyu Qiao(乔轩雨)1, Chenyang Ma(马辰洋)2, and Guodong Liu(刘国栋)2   

  1. 1 Key Laboratory of Rare Earths, Ganjiang Innovation Academy, Chinese Academy of Sciences, Ganzhou 341000, China;
    2 School of Science, Hebei University of Technology, Tianjin 300130, China
  • Received:2025-11-21 Revised:2026-01-06 Accepted:2026-01-09 Published:2026-07-21
  • Contact: Zhaojun Mo E-mail:mozhaojun@gia.cas.cn
  • Supported by:
    This work was supported by the Light of the Soviet Area Innovation Leading Talent Program (Grant No. E23HB00101), the National Natural Science Foundation of China (Grant No. 52501262), and the Key Laboratory of Rare Earths, Chinese Academy of Sciences.

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摘要： Hydrogen, as a clean energy carrier, requires liquefaction at 20-77 K, a process that is energy-intensive and traditionally dependent on conventional refrigeration methods. Magnetocaloric refrigeration offers a promising alternative, especially when using permanent magnets as the magnetic field source, which can significantly simplify system design and reduce operational costs. Designing magnetocaloric materials with magnetic ordering temperatures within the hydrogen liquefaction range and exhibiting superior magnetocaloric effects under low magnetic fields is essential for advancing sustainable energy technologies. This study presents an in-depth investigation of the enhanced low-field magnetocaloric effect (MCE) in $R$Cu$_{2-x}$Co$_{x}$ ($R = {\rm rare}$-earth) compounds. The results indicate that Co doping significantly modifies orbital hybridization and magnetic properties, which in turn improves the MCE under low fields. Experimental data confirm that Co-doped compounds show MCE performance at low fields. For instance, under a varying magnetic field of 0-2 T, the volumetric magnetic entropy change of the ErCu$_{1.75}$Co$_{0.25}$ compound reaches 0.12 J$\cdot$cm$^{-3}\cdot$K$^{-1}$. First-principles calculations provide further insights into the electronic density of states and magnetic exchange interactions, clarifying the mechanisms behind the enhanced MCE.

关键词: magnetocaloric effect, hydrogen liquefaction, low magnetic fields, first-principles calculations

Abstract: Hydrogen, as a clean energy carrier, requires liquefaction at 20-77 K, a process that is energy-intensive and traditionally dependent on conventional refrigeration methods. Magnetocaloric refrigeration offers a promising alternative, especially when using permanent magnets as the magnetic field source, which can significantly simplify system design and reduce operational costs. Designing magnetocaloric materials with magnetic ordering temperatures within the hydrogen liquefaction range and exhibiting superior magnetocaloric effects under low magnetic fields is essential for advancing sustainable energy technologies. This study presents an in-depth investigation of the enhanced low-field magnetocaloric effect (MCE) in $R$Cu$_{2-x}$Co$_{x}$ ($R = {\rm rare}$-earth) compounds. The results indicate that Co doping significantly modifies orbital hybridization and magnetic properties, which in turn improves the MCE under low fields. Experimental data confirm that Co-doped compounds show MCE performance at low fields. For instance, under a varying magnetic field of 0-2 T, the volumetric magnetic entropy change of the ErCu$_{1.75}$Co$_{0.25}$ compound reaches 0.12 J$\cdot$cm$^{-3}\cdot$K$^{-1}$. First-principles calculations provide further insights into the electronic density of states and magnetic exchange interactions, clarifying the mechanisms behind the enhanced MCE.

Key words: magnetocaloric effect, hydrogen liquefaction, low magnetic fields, first-principles calculations

中图分类号:  (Magnetocaloric effect, magnetic cooling)

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75.47.Pq (Other materials)