中国物理B ›› 2025, Vol. 34 ›› Issue (6): 67505-067505.doi: 10.1088/1674-1056/adcaa4

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Multiferroicity and thermal expansion of the layered metal-organic framework [NH4Cl]2[Ni(HCOO)2(NH3)2]

Dan Cheng(程丹), Yingjie He(何英杰), Shuang Liu(刘爽), Na Su(苏娜), and Young Sun(孙阳)†   

  1. Department of Applied Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, China
  • 收稿日期:2025-03-20 修回日期:2025-04-01 接受日期:2025-04-09 出版日期:2025-05-16 发布日期:2025-05-30
  • 通讯作者: Young Sun E-mail:youngsun@cqu.edu.cn
  • 基金资助:
    Project supported by the National Key Research and Development Program of China (Grant No. 2021YFA1400303) and the National Natural Science Foundation of China (Grant No. 12227806).

Multiferroicity and thermal expansion of the layered metal-organic framework [NH4Cl]2[Ni(HCOO)2(NH3)2]

Dan Cheng(程丹), Yingjie He(何英杰), Shuang Liu(刘爽), Na Su(苏娜), and Young Sun(孙阳)†   

  1. Department of Applied Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, China
  • Received:2025-03-20 Revised:2025-04-01 Accepted:2025-04-09 Online:2025-05-16 Published:2025-05-30
  • Contact: Young Sun E-mail:youngsun@cqu.edu.cn
  • Supported by:
    Project supported by the National Key Research and Development Program of China (Grant No. 2021YFA1400303) and the National Natural Science Foundation of China (Grant No. 12227806).

摘要: We have investigated the magnetic, dielectric, pyroelectric, and thermal expansion properties of a layered perovskite metal-organic framework, [NH$_{4}$Cl]$_{2}$[Ni(HCOO)$_{2}$(NH$_{3}$)$_{2}$]. The material undergoes three phase transitions including a canted antiferromagnetic transition at $\sim 36 $ K, and two successive structural transitions around 100 K and 110 K, respectively. The temperature dependence of dielectric permittivity and pyroelectric current suggests that the structural transitions induce weak ferroelectricity along the $c$-axis and antiferroelectricity in the ab plane. A negative thermal expansion along the $c$-axis is observed between two structural phase transitions, which is ascribed to the abnormal shrinkage of interlayer hydrogen bonding length. Moreover, the ferroelectric/antiferroelectric phase transition temperature shifts towards a higher temperature under a magnetic field, suggesting certain magnetoelectric coupling in the paramagnetic phase. Our study suggests that the layered metal-organic frameworks provide a unique playground for exploring exotic physical properties such as multiferroicity and abnormal thermal expansion.

关键词: multiferroic, thermal expansion, metal-organic framework

Abstract: We have investigated the magnetic, dielectric, pyroelectric, and thermal expansion properties of a layered perovskite metal-organic framework, [NH$_{4}$Cl]$_{2}$[Ni(HCOO)$_{2}$(NH$_{3}$)$_{2}$]. The material undergoes three phase transitions including a canted antiferromagnetic transition at $\sim 36 $ K, and two successive structural transitions around 100 K and 110 K, respectively. The temperature dependence of dielectric permittivity and pyroelectric current suggests that the structural transitions induce weak ferroelectricity along the $c$-axis and antiferroelectricity in the ab plane. A negative thermal expansion along the $c$-axis is observed between two structural phase transitions, which is ascribed to the abnormal shrinkage of interlayer hydrogen bonding length. Moreover, the ferroelectric/antiferroelectric phase transition temperature shifts towards a higher temperature under a magnetic field, suggesting certain magnetoelectric coupling in the paramagnetic phase. Our study suggests that the layered metal-organic frameworks provide a unique playground for exploring exotic physical properties such as multiferroicity and abnormal thermal expansion.

Key words: multiferroic, thermal expansion, metal-organic framework

中图分类号:  (Magnetoelectric effects, multiferroics)

  • 75.85.+t
77.84.-s (Dielectric, piezoelectric, ferroelectric, and antiferroelectric materials) 81.07.Pr (Organic-inorganic hybrid nanostructures) 75.50.Ee (Antiferromagnetics)