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173 results on '"Wu, Si-Guo"'

2. Rectangle-like hysteresis in a Dysprosium Metallacrown Magnet with Linear F-Dy-F Anisotropic Moiety

Author

Wu, Si-Guo, Ruan, Ze-Yu, Zheng, Jie-Yu, Huang, Guo-Zhang, Vieru, Veacheslav, Chen, Yan-Cong, Ho, Le Tuan Anh, Liu, Jun-Liang, Chibotaru, Liviu F., and Tong, Ming-Liang

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Single-molecule magnets (SMMs) exhibiting open hysteresis loops may potentially apply to molecule-based information processing and storage. However, the capacity to retain magnetic memory is always limited by zero-field quantum tunneling of magnetization (QTM). Herein, a well-designed dysprosium metallacrown SMM, consisting of an endohedral approximate linear F-Dy-F strong anisotropic moiety in a peripheral [15-MCNi-5] metallacrown (MC), is reported with the largest reversal barrier of 1060 cm-1 among d-f SMMs. Rectangle-like hysteresis loops are observed with the huge squareness (remanence/saturation magnetization) up to 97% at 2 K. More importantly, zero-field QTM step is phenomenologically removed by minimizing the dipole coupling and hyperfine interactions. The results demonstrate for the first time that zero-field QTM step can be eliminated via manipulating the ligand field and vanishing the external magnetic perturbations, which illuminates a promising blueprint for developing high-performance SMMs.

Published
2021

5. Field-induced oscillation of magnetization blocking in holmium metallacrown magnet

Author

Wu, Si-Guo, Ruan, Ze-Yu, Huang, Guo-Zhang, Zheng, Jie-Yu, Vieru, Veacheslav, Taran, Gheorghe, Wang, Jin, Chen, Yan-Cong, Liu, Jun-Liang, Ho, Le Tuan Anh, Chibotaru, Liviu F., Wernsdorfer, Wolfgang, Chen, Xiao-Ming, and Tong, Ming-Liang

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science, Physics - Chemical Physics
Abstract

Single-molecule magnets (SMMs) are promising elements for quantum informatics. In the presence of strong magnetic anisotropy, they exhibit magnetization blocking - a magnetic memory effect at the level of a single molecule. Recent studies have shown that the SMM performance scales with the height of magnetization blocking barrier. By employing molecular engineering this can be significantly modified, remaining independent from other external factors such as magnetic field. Taking advantage of hyperfine coupling of electronic and nuclear spins further enhances their functionality, however, a poor understanding of relaxation mechanisms in such SMMs limits the exploitation of nuclear-spin molecular qubits. Here we report the opening discovery of field-dependent oscillation of the magnetization blocking barrier in a new holmium metallacrown magnet driven by the switch of relaxation mechanisms involving hyperfine interaction. Single-crystal magnetic hysteresis measurements combined with first-principles calculations reveal an activated temperature dependence of magnetic relaxation dominated either by incoherent quantum tunneling of magnetization at anti-crossing points of exchange-hyperfine states or by Orbach-like processes at crossing points. We demonstrate that these relaxation mechanisms can be consecutively switched on and off by increasing the external field, which paves a way for manipulating the magnetization dynamics of SMMs using hyperfine interaction., Comment: 6 pages, 4 figures

Published
2020

7. Carbonate-Bridged Dinuclear and Trinuclear Dysprosium(III) Single-Molecule Magnets

Author

Lu, Guang, Chen, Yan-Cong, Wu, Si-Guo, Huang, Guo-Zhang, Liu, Jun-Liang, Ni, Zhao-Ping, and Tong, Ming-Liang

Subjects
Condensed Matter - Materials Science, Physics - Chemical Physics
Abstract

In 2016, we reported a single-ion magnet [Dy(bbpen)Br] with an energy barrier over 1000 K. Here a dimeric [Dy2(mu-CO3)(bbpen)2(H2O)].H2O.CH3OH (1) and a trimeric [Dy3(mu3-CO3)(bppen)3](CF3SO3).H2O (2) single-molecule magnets (SMMs) were obtained through replacing the Br- anion with the carbonate bridge. Their effective relaxation barriers at zero dc field are decrease to 51 K and 422 K, respectively, which are consist with their structural modifications.

Published
2018

8. Two 2D spin-crossover coordination polymers constructed by [Pd(SCN)4]2− building blocks.

Author

Xie, Kai-Ping, Peng, Zhi-Zhen, Ruan, Ze-Yu, Fan, Wei-Ding, Chen, Yan-Ru, Zheng, Xiao-Dan, Zou, Yu-Bo, Wu, Si-Guo, and Xiao, Zi-Cheng

Subjects
PYRIDINE
Abstract

Two new two-dimensional (2D) coordination polymers, [FeII(L)2{PdII(SCN)4}] (L1 = 2-methoxypyrazine, 1; and L2 = (E)-3-(phenyldiazenyl)pyridine, 2), were successfully constructed by using square-planar [Pd(SCN)4]2− building blocks. Complex 1 exhibits complete and one-step spin-crossover (SCO) behavior, while 2 exhibits incomplete and two-step SCO behavior. Further structural insight into this synergy reveals that the flat/flexing [Fe{Pd(SCN)4}]∞ sheets in 1 and 2 are stabilized by interlayered/intralayered supramolecular interactions. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Spin‐State Control in Dysprosium(III) Metallacrown Magnets via Thioacetal Modification.

Author

Deng, Wei, Wu, Si‐Guo, Ruan, Ze‐Yu, Gong, Ya‐Ping, Du, Shan‐Nan, Wang, Hai‐Ling, Chen, Yan‐Cong, Zhang, Wei‐Xiong, Liu, Jun‐Liang, and Tong, Ming‐Liang

Subjects
*SINGLE molecule magnets, *MAGNETS, *DYSPROSIUM, *AB-initio calculations, *MOLECULAR interactions, *SUPERCONDUCTING magnets
Abstract

Integrating controllable spin states into single‐molecule magnets (SMMs) enables precise manipulation of magnetic interactions at a molecular level, but remains a synthetic challenge. Herein, we developed a 3d–4f metallacrown (MC) magnet [DyNi5(quinha)5(Clsal)2(py)8](ClO4) ⋅ 4H2O (H2quinha=quinaldichydroxamic acid, HClsal=5‐chlorosalicylaldehyde) wherein a square planar NiII is stabilized by chemical stacking. Thioacetal modification was employed via post‐synthetic ligand substitutions and yielded [DyNi5(quinha)5(Clsaldt)2(py)8](ClO4) ⋅ 3H2O (HClsaldt=4‐chloro‐2‐(1,3‐dithiolan‐2‐yl)phenol). Thanks to the additional ligations of thioacetal onto the NiII site, coordination‐induced spin state switching (CISSS) took place with spin state altering from low‐spin S=0 to high‐spin S=1. The synergy of CISSS effect and magnetic interactions results in distinct energy splitting and magnetic dynamics. Magnetic studies indicate prominent enhancement of reversal barrier from 57 cm−1 to 423 cm−1, along with hysteresis opening and an over 200‐fold increment in coercive field at 2 K. Ab initio calculations provide deeper insights into the exchange models and rationalize the relaxation/tunnelling pathways. These results demonstrate here provide a fire‐new perspective in modulating the magnetization relaxation via the incorporation of controllable spin states and magnetic interactions facilitated by the CISSS approach. [ABSTRACT FROM AUTHOR]

Published
2024
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14. Cyanometallic charge engineering in spin crossover metal–organic frameworks.

Author

Lyu, Bang-Heng, Xie, Kai-Ping, Cui, Wen, Chen, Yan-Cong, Chen, Guan-Xi, Wu, Si-Guo, and Tong, Ming-Liang

Subjects
SPIN crossover, METAL-organic frameworks, ENGINEERING, DESOLVATION
Abstract

In this study, we successfully synthesize cationic/neutral/anionic inverse-Hofmann-type spin crossover (SCO) frameworks with 1,1,2,2-tetrakis(4-(pyridine-4-yl)phenyl)-ethene ligand by means of cyanometallic charge engineering strategy. The cationic and neutral frameworks exhibit single-step thermally induced spin transition behaviors, while the SCO capability of anionic framework can be aroused by partial desolvation. This strategy provides a new idea to construct ionic SCO frameworks and extends the toolkit for SCO materials. [ABSTRACT FROM AUTHOR]

Published
2024
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29. Opening Magnetic Hysteresis by Axial Ferromagnetic Coupling: From Mono‐Decker to Double‐Decker Metallacrown

Author

Wang, Jin, primary, Li, Quan‐Wen, additional, Wu, Si‐Guo, additional, Chen, Yan‐Cong, additional, Wan, Rui‐Chen, additional, Huang, Guo‐Zhang, additional, Liu, Yang, additional, Liu, Jun‐Liang, additional, Reta, Daniel, additional, Giansiracusa, Marcus J., additional, Wang, Zhen‐Xing, additional, Chilton, Nicholas F., additional, and Tong, Ming‐Liang, additional

Published
2021
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30. Fascinating interlocked triacontanuclear giant nanocages

Author

Bala, Sukhen, primary, Akhtar, Sohel, additional, Liu, Jun-Liang, additional, Huang, Guo-Zhang, additional, Wu, Si-Guo, additional, De, Avik, additional, Das, Krishna Sundar, additional, Saha, Sayan, additional, Tong, Ming-Liang, additional, and Mondal, Raju, additional

Published
2021
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49. A spin-crossover phenomenon in a 2D heterometallic coordination polymer with [Pd(SCN)4]2− building blocks.

Author

Xie, Kai-Ping, Wu, Si-Guo, Wang, Long-Fei, Huang, Guo-Zhang, Ni, Zhao-Ping, and Tong, Ming-Liang

Subjects
*COORDINATION polymers, *SUPRACHIASMATIC nucleus, *ATMOSPHERIC pressure
Abstract

Two new two-dimensional (2D) coordination polymers, [FeII(L)2{PdII(SCN)4}] (L1 = 3-(9-anthracenyl)-pyridine (1) and L2 = 4-(9-anthracenyl)-pyridine (2)), were constructed by employing square-planar [Pd(SCN)4]2− building blocks. Compound 1 exhibits a complete spin-crossover (SCO) behaviour under normal atmospheric pressure, and represents the first SCO example in a 2D system containing [Pd(SCN)4]2− units. In contrast, compound 2 only shows paramagnetic behaviour at measured temperatures. It is clear that the fine-tuning of the monodentate ligand can modulate the ligand field and packing fashions, which sheds light on developing new SCO materials. [ABSTRACT FROM AUTHOR]

Published
2021
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