Significant Zero Thermal Expansion Via Enhanced Magnetoelastic Coupling in Kagome Magnets

Jiawang Xu; Zhan Wang; He Huang; Zhuolin Li; Xiang Chi; Dingsong Wang; Jingyan Zhang; Xinqi Zheng; Jun Shen; Wenda Zhou; Yang Gao; Jianwang Cai; Tongyun Zhao; Shouguo Wang; Ying Zhang; Baogen Shen

doi:10.1002/adma.202208635

Significant Zero Thermal Expansion Via Enhanced Magnetoelastic Coupling in Kagome Magnets

Adv Mater. 2023 Feb;35(8):e2208635. doi: 10.1002/adma.202208635. Epub 2022 Dec 25.

Authors

Jiawang Xu^{1

2}, Zhan Wang¹, He Huang³, Zhuolin Li¹, Xiang Chi², Dingsong Wang³, Jingyan Zhang³, Xinqi Zheng³, Jun Shen⁴, Wenda Zhou⁵, Yang Gao⁵, Jianwang Cai¹, Tongyun Zhao¹, Shouguo Wang⁵, Ying Zhang^{1

2}, Baogen Shen^{1

5

6}

Affiliations

¹ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
² Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China.
³ Beijing Advanced Innovation Center for Materials Genome Engineering, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
⁴ Department of Energy and Power Engineering, School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, China.
⁵ School of Materials Science and Engineering, Anhui University, Hefei, Anhui, 230601, China.
⁶ Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang, 315201, China.

PMID: 36567404
DOI: 10.1002/adma.202208635

Abstract

Zero-thermal-expansion (ZTE) alloys, as dimensionally stable materials, are urgently required in many fields, particularly in highly advanced modern industries. In this study, high-performance ZTE with a negligible coefficient of thermal expansion a_v as small as 2.4 ppm K^-1 in a broad temperature range of 85-245 K is discovered in Hf_0.85 Ta_0.15 Fe₂ C_0.01 magnet. It is demonstrated that the addition of trace interstitial atom C into Ta-substituted Hf_0.85 Ta_0.15 Fe₂ exhibits significant capability to tune the normal positive thermal expansion into high-performance ZTE via enhanced magnetoelastic coupling in stabilized ferromagnetic structure. Moreover, direct observation of the magnetic transition between ferromagnetic and triangular antiferromagnetic states via Lorentz transmission electron microscopy, along with corresponding theoretical calculations, further uncovers the manipulation mechanism of ZTE and negative thermal expansion. A convenient and effective method to optimize thermal expansion and achieve ZTE with interstitial C addition may result in broadened applications based on the strong correlation between the magnetic properties and crystal structure.

Keywords: kagome magnets; magnetic transition; magnetoelastic coupling; negative thermal expansion; zero thermal expansion.

Abstract

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