The kagome lattice, composed of a planar array of corner-sharing triangles, is one of the most geometrically frustrated lattices. The realization of a spin S = 1/2 kagome lattice antiferromagnet is of particular interest because it may host an exotic form of matter, a quantum spin liquid state, which shows long-range entanglement and no magnetic ordering down to 0 K. A few S = 1/2 kagome lattice antiferromagnets exist, typically based on Cu2+, d9 compounds, though they feature structural imperfections. Herein, we present the synthesis of (CH3NH3)2NaTi3F12, which comprises an S = 1/2 kagome layer that exhibits only one crystallographically distinct Ti3+, d1 site, and one type of bridging fluoride. A static positional disorder is proposed for the interlayer CH3NH3+. No structural phase transitions were observed from 1.8 K to 523 K. Despite its spin-freezing behaviour, other features—including its negative Curie–Weiss temperature and a lack of long-range ordering—imply that this compound is a highly frustrated magnet with unusual magnetic phase behaviours.
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Crystallographic data for the structures reported in this Article have been deposited at the Cambridge Crystallographic Data Centre, under deposition numbers CCDC 1950701 (1-Ti, 100 K) and 1950702 (1-Ti, 298 K). Copies of the data can be obtained free of charge via https://www.ccdc.cam.ac.uk/structures/. All data generated or analysed during this study are included in this published article and its Supplementary Information files.
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Studies were supported by the Beckman Foundation as part of a Beckman Young Investigator Award to H.S.L. Single-crystal diffraction experiments were performed at the Georgia Institute of Technology SCXRD facility, established with funding from the Georgia Institute of Technology. We thank M. Mourigal for providing access to a PPMS. This work was performed in part at the Georgia Tech Institute for Electronics and Nanotechnology, a member of the National Nanotechnology Coordinated Infrastructure (NNCI), which is supported by the National Science Foundation (grant ECCS-1542174). The low-temperature PXRD experiment was conducted at the Center for Nanophase Materials Sciences, which is a US Department of Energy (DOE) Office of Science User Facility. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. We thank Q. Zhang and J. K. Keum for their help with neutron powder diffraction and low-temperature PXRD studies, respectively.
The authors declare no competing interests.
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Jiang, N., Ramanathan, A., Bacsa, J. et al. Synthesis of a d1-titanium fluoride kagome lattice antiferromagnet. Nat. Chem. 12, 691–696 (2020). https://doi.org/10.1038/s41557-020-0490-8
Nature Chemistry (2020)