The magnetic origin of multiferroic Y2CoMnO6

Ting Jia1, Zhi Zeng1,2, a), X. G. Li3, and H. Q. Lin4

1Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China

• 2Department of Physics, University of Science and Technology of China, Hefei 230026, China
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• 3Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, University of Science and Technology of China, Hefei 230026, China
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• 4Beijing Computational Science Research Center, Beijing 100084, China
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• a)Author to whom correspondence should be addressed. Electronic mail: zzeng@theory.issp.ac.cn.

ABSTRACT

It has been found experimentally that the ferroelectricity in Y2CoMnO6 is driven by a magnetic ordering of collinear up-up-down-down (↑↑↓↓$\uparrow \uparrow \downarrow \downarrow$). Here, the origin of the magnetism and thereby ferroelectricity is studied using first-principles calculations. We first confirm that the experimentally observed ↑↑↓↓$\uparrow \uparrow \downarrow \downarrow$ antiferromagnetic structure is the ground state of Y2CoMnO6. Additionally, both the Co2+ and Mn4+ are in the high-spin state. By analyzing the exchange coupling and corresponding pathways, we conclude that the ↑↑↓↓$\uparrow \uparrow \downarrow \downarrow$ spin order in Y2CoMnO6 originates from a subtle competition between the ferromagnetic Co-O-Mn super-exchange and antiferromagnetic Co-Mn direct-exchange along c axis.

 https://sci-hub.tw/https://aip.scitation.org/doi/abs/10.1063/1.4915095?journalCode=jap