Pressure-induced charge orders and their coupling to magnetism in hexagonal multiferroic LuFe2O4

Fengliang Liu; Yiqing Hao; Jinyang Ni; Yongsheng Zhao; Dongzhou Zhang; Gilberto Fabbris; Daniel Haske; Shaobo Cheng; Xiaoshan Xu; Lifeng Yin; Hongjun Xiang; Jun Zhao; Xujie Lü; Wenbin Wang; Jian Shen; Wenge Yang

arXiv · 2112.10036

Pressure-induced charge orders and their coupling to magnetism in hexagonal multiferroic LuFe2O4

Fengliang Liu·Yiqing Hao·Jinyang Ni·Yongsheng Zhao·Dongzhou Zhang·Gilberto Fabbris·Daniel Haske·Shaobo Cheng·Xiaoshan Xu·Lifeng Yin·Hongjun Xiang·Jun Zhao·Xujie Lü·Wenbin Wang·Jian Shen·Wenge Yang

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Abstract

Hexagonal LuFe2O4 is a promising charge-order (CO) driven multiferroic material with high charge and spin ordering temperatures. The coexisting charge and spin orders on Fe3+/Fe2+ sites result in novel magnetoelectric behaviors, but the coupling mechanism between the charge and spin orders remains elusive. Here, by tuning external pressure, we reveal three correlated spin-charge ordered phases in LuFe2O4: i) a centrosymmetric incommensurate three-dimensional CO with ferrimagnetism, ii) a non-centrosymmetric incommensurate quasi-two-dimensional CO with ferrimagnetism, and iii) a centrosymmetric commensurate CO with antiferromagnetism. Experimental in-situ single-crystal X-ray diffraction and X-ray magnetic circular dichroism measurements combined with density functional theory calculations suggest that the charge density redistribution caused by pressure-induced compression in the frustrated double-layer [Fe2O4] cluster is responsible for the correlated spin-charge phase transitions. The pressure-enhanced effective Coulomb interactions among Fe-Fe bonds drive the frustrated (1/3, 1/3) CO to a less frustrated (1/4, 1/4) CO, which induces the ferrimagnetic to antiferromagnetic transition. Our results not only elucidate the coupling mechanism among charge, spin and lattice degrees of freedom in LuFe2O4 but also provide a new way to tune the spin-charge orders in a highly controlled manner.

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Fengliang Liu, Yiqing Hao, Jinyang Ni, Yongsheng Zhao, Dongzhou Zhang, Gilberto Fabbris, Daniel Haske, Shaobo Cheng, Xiaoshan Xu, Lifeng Yin, Hongjun Xiang, Jun Zhao, Xujie Lü, Wenbin Wang, Jian Shen, Wenge Yang. 2021-12-19. Pressure-induced charge orders and their coupling to magnetism in hexagonal multiferroic LuFe2O4. https://arxiv.org/abs/2112.10036

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