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

Authors

• Fengliang Liu, Fudan University, Center for High Pressure Science and Technology Advanced Research, Nanchang University
• Yiqing Hao, Fudan University,
• Jinyang Ni, Fudan University,
• Yongsheng Zhao, Center for High Pressure Science and Technology Advanced Research
• Dongzhou Zhang, University of Hawaii Manoa
• Gilberto Fabbris, Argonne National Laboratory
• Daniel Haskel, Argonne National Laboratory
• Shaobo Cheng, Brookhaven National Laboratory
• Xiaoshan XuFollow
• Lifeng Yin, Fudan University, Collaborative Innovation Center of Advanced Microstructures, Shanghai Qi Zhi Institute, Shanghai Research Center for Quantum Sciences
• Hongjun Xiang, Fudan University, Collaborative Innovation Center of Advanced Microstructures
• Jun Zhao, Fudan University, Collaborative Innovation Center of Advanced Microstructures, Shanghai Qi Zhi Institute
• Xujie Lü
• Wenbin Wang, Fudan University, Collaborative Innovation Center of Advanced Microstructures, Shanghai Qi Zhi Institute, Shanghai Research Center for Quantum Sciences
• Jian Shen, Fudan University, Collaborative Innovation Center of Advanced Microstructures, Shanghai Qi Zhi Institute, Shanghai Research Center for Quantum Sciences
• Wenge Yang, Center for High Pressure Science and Technology Advanced Research

Document Type

Article

Date of this Version

1-7-2023

Citation

npj Quantum Materials (2023) 8:1 ; https://doi.org/10.1038/s41535-022-00522-x

Comments

Open access.

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 magnetoelectric behaviors, but the coupling mechanism between the charge and spin orders remains elusive. Here, by tuning external pressure, we reveal three charge-ordered phases with suggested correlation to magnetic orders 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.