Reentrant Spin Glass and Large Coercive Field Observed in a Spin Integer Dimerized Honeycomb Lattice |
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| Authors: | Yuan-Qi Zhai Yi-Fei Deng Zhendong Fu Erxi Feng Yixi Su Takuya Shiga Hiroki Oshio Yan-Zhen Zheng |
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| Affiliation: | 1. Frontier Institute of Science and Technology (FIST), Xi'an Jiaotong University Shenzhen Research School, State Key Laboratory for Mechanical Behavior of Materials, MOE Key Laboratory for Nonequilibrium Synthesis of Condensed Matter, Xi'an Jiaotong University, 99 Yanxiang Road, Xi'an, Shaanxi, 710054 China;2. Neutron Platform, Songshan Lake Materials Laboratory, Dongguan, 523808 China;3. Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Lichtenbergstraße 1, Garching, 85747 Germany;4. Graduate School of Pure and Applied Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, 305-8571 Japan;5. State Key Laboratory of Fine Chemicals, Dalian University of Technology, 2 Linggong Rd., Dalian, 116024 China |
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| Abstract: | 2D magnetic materials with dimerized honeycomb lattices can be treated as mixed-spin square lattices, in which a quantum phase transition may occur to realize the Bose–Einstein condensation of magnons under reachable experimental conditions. However, this has never been successfully realized with integer spin centers. Herein, a spin integer (S = 2) dimerized honeycomb lattice in an iron(II)-azido compound [Fe(4-etpy)2(N3)2]n (FEN, 4-etpy = 4-ethylpyridine) is realized. Morphology characterization by transmission electron microscopy, scanning electron microscopy, and atomic force microscopy spectroscopies show that the thinnest place of the sample is ≈13 nm, which is equal to ten layers of the compound. In contrast to the common magnetic properties of long-range magnetic ordering, Mössbauer and polarized neutron scattering studies reveal that FEN exhibits a reentrant spin glass behavior owing to competing ferro- and antiferromagnetic exchange-coupling interactions within the lattice. Two spin glass phases with disparate canting angles are characterized at 39 and 28 K, respectively. By using Curély's model, two exchange-coupling constants (J1 = +35.8 cm−1 and J2 = −3.7 cm−1) can be simulated. Moreover, a very large coercive field of ≈1.9 Tesla is observed at 2 K, making FEN a “very hard” van der Waals 2D magnetic material. |
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| Keywords: | 2D frustrated magnets dimerized honeycomb lattices iron(II) neutron scattering spin glass |
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