Search

Your search keyword '"Han Jun-Bo"' showing total 150 results
Start Over Author "Han Jun-Bo"
150 results on '"Han Jun-Bo"'

1. Electrical control of exchange bias in Fe3GaTe2/Fe3GeTe2 van der Waals heterostructures.

Author

Chen, Hongjing, Xing, Yuntong, Wang, Xia, Wang, Guan, Wu, Jinsong, Zhang, Aoyu, Hao, Qinghua, Cai, Menghao, Chen, Xiaodie, Li, Longde, Chen, Wenzhanhong, and Han, Jun-Bo

Subjects
EXCHANGE bias, KERR magneto-optical effect, MAGNETIC storage, MAGNETIC coupling, MAGNETIC circular dichroism
Abstract

Magnetic heterojunctions with large exchange bias have promising applications in magnetic sensing and data storage. Ferromagnetic/antiferromagnetic (FM/AFM) heterojunctions are often used to generate exchange bias. However, the requirement of thermal manipulation makes controlling exchange bias in FM/AFM heterojunctions inconvenient. Herein, a Fe3GeTe2/Fe3GaTe2 FM/FM heterojunction is constructed to generate large exchange bias and reflected magnetic circular dichroism and magneto-optical Kerr effect techniques are used for the magnetic characterization of the heterojunction. The results show that strong magnetic coupling occurs at the Fe3GeTe2/Fe3GaTe2 interface when the temperature is <80 K. By fixing the spin direction of Fe3GaTe2, large exchange bias can be generated in Fe3GeTe2 because of the magnetic pinning effect. Furthermore, the strength of exchange bias can be manipulated by applying an ultralow current between Fe3GeTe2 and Fe3GaTe2 layers without changing the temperature. These results provide potential ways for generating and manipulating exchange bias in two-dimensional (2D) materials and pave the way for implementing the 2D van der Waals exchange bias effect in spintronic devices. [ABSTRACT FROM AUTHOR]

Published
2025
Full Text
View/download PDF

4. All-in-One Magneto-optical Memory Arrays Based on a Two-Dimensional Ferromagnetic Metal

Author

Hao, Qinghua, Cai, Menghao, Dai, Hongwei, Xing, Yuntong, Chen, Hongjing, Zhang, Aoyu, Li, Longde, Chenwen, Zhanhong, Wang, Xia, and Han, Jun-Bo

Abstract

Two-dimensional (2D) van der Waals (vdW) magnetic materials with atomic-scale thickness and smooth interfaces promise the possibility of developing high-density, energy-efficient spintronic devices. However, it remains a challenge to effectively control the perpendicular magnetic anisotropy (PMA) of 2D vdW ferromagnetic materials, as well as the integration of multiple memory cells. Here, we report highly efficient magneto-optical memory arrays by utilizing the huge spin–orbit torques (SOT) induced by the in-plane current in Fe3GeTe2(FGT) flake. The device is constructed from individual FGT flakes without heavy metal assistance and allows for a low current density. The magneto-optical memory arrays implement nonvolatile memories for three bits and can be repeatedly scrubbed for “writing” and “reading”. Besides, we show that FGT nanoflakes possess current-controlled volatile switching behavior at zero magnetic field. These results provide a solution for the next generation of all-vdW-scalable, high-performance spintronic logic devices and SOT-Magnetic Random Access Memory (MRAM).

Published
2024
Full Text
View/download PDF

6. Manipulation and Optical Detection of Artificial Topological Phenomena in 2D Van der Waals Fe5GeTe2/MnPS3 Heterostructures

Author

Chen, Xiaodie, primary, Wang, Haoyun, additional, Li, Manshi, additional, Hao, Qinghua, additional, Cai, Menghao, additional, Dai, Hongwei, additional, Chen, Hongjing, additional, Xing, Yuntong, additional, Liu, Jie, additional, Wang, Xia, additional, Zhai, Tianyou, additional, Zhou, Xing, additional, and Han, Jun‐Bo, additional

Published
2023
Full Text
View/download PDF

8. Manipulating Exchange Bias in 2D Magnetic Heterojunction for High-performance Robust Memory Applications

Author

Ye, Lei, primary, Huang, Xinyu, additional, Zhang, Luman, additional, Tong, Lei, additional, Li, Zheng, additional, Peng, Zhuiri, additional, Lin, Runfeng, additional, Xue, Kan-Hao, additional, Dai, Hongwei, additional, Cheng, Hui, additional, Branco, Danilo de Camargo, additional, Xu, Jian-Bin, additional, Han, Jun-Bo, additional, Cheng, Gary, additional, Miao, Xiang Shui, additional, and Shi, Wenhao, additional

Published
2022
Full Text
View/download PDF

9. Manipulation and Optical Detection of Artificial Topological Phenomena in 2D Van der Waals Fe5GeTe2/MnPS3 Heterostructures.

Author

Chen, Xiaodie, Wang, Haoyun, Li, Manshi, Hao, Qinghua, Cai, Menghao, Dai, Hongwei, Chen, Hongjing, Xing, Yuntong, Liu, Jie, Wang, Xia, Zhai, Tianyou, Zhou, Xing, and Han, Jun‐Bo

Subjects
MAGNETIC domain, MAGNETIC structure, SPHEROMAKS, ANOMALOUS Hall effect, MAGNETIC materials, MAGNETIC circular dichroism, HYSTERESIS loop
Abstract

2D ferromagnet is a good platform to investigate topological effects and spintronic devices owing to its rich spin structures and excellent external‐field tunability. The appearance of the topological Hall Effect (THE) is often regarded as an important sign of the generation of chiral spin textures, like magnetic vortexes or skyrmions. Here, interface engineering and an in‐plane current are used to modulate the magnetic properties of the nearly room‐temperature 2D ferromagnet Fe5GeTe2. An artificial topology phenomenon is observed in the Fe5GeTe2/MnPS3 heterostructure by using both anomalous Hall Effect and reflective magnetic circular dichroism (RMCD) measurements. Through tuning the applied current and the RMCD laser wavelength, the amplitude of the humps and dips observed in the hysteresis loops can be modulated accordingly. Magnetic field‐dependent hysteresis loops demonstrate that the observed artificial topological phenomena are induced by the generation and annihilation of the magnetic domains. This work provides an optical method for investigating the topological‐like effects in magnetic structures and proposes an effective way to modulate the magnetic properties of magnetic materials, which is important for developing magnetic and spintronic devices in van der Waals magnetic materials. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

21. Thermostability and photoluminescence of Dy(iii) single-molecule magnets under a magnetic field† †Electronic supplementary information (ESI) available: Additional magnetic data, additional figures and computational details. CCDC 1446709–1446713. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc01157h

Author

Bi, Ye, Chen, Cheng, Zhao, Yi-Fang, Zhang, Yi-Quan, Jiang, Shang-Da, Wang, Bing-Wu, Han, Jun-Bo, Sun, Jun-Liang, Bian, Zu-Qiang, Wang, Zhe-Ming, and Gao, Song

Subjects
Chemistry
Abstract

A series of promising multifunctional lanthanide single-molecule magnets (SMMs). Lanthanide luminescence under a pulsed magnetic field for SMMs is examined for the first time., A series of compounds [ADyL4]·[solvent] composed of a dysprosium(iii) ion coordinated by four chelated naphthyridine-like ligands (L = 4-hydroxy-8-methyl-1,5-naphthyridine-3-carbonitrile) and an alkali metal ion (A = Na, K, Rb, Cs) were synthesized and characterized. They behave as single-molecule magnets under a zero dc field with an effective energy barrier of around 95 cm–1. Meanwhile, the main part, [ADyL4], of these SMMs is thermostable and sublimable. The geometric structures of three sublimed compounds are identical to the original ones without solvents, which is confirmed by X-ray diffraction using single crystal and powder samples. The static and dynamic magnetic properties remain unchanged before and after sublimation. Luminescence measurements at 5–77 K were performed to verify the energy gap between low-lying states and to understand the pathway of the thermal relaxation process of magnetization, as well as to inspect the tiny variation in magnetic sublevels for the ground term of Dy(iii). The photoluminescence spectra under a magnetic field (0–36 T) for the Dy-SMMs are investigated for the first time. The energy splitting of the two lowest sublevels of the ground term 6H15/2 of Dy(iii) are analyzed using the Zeeman formula.

Published
2016

22. Substrate-modulated ferromagnetism of two-dimensional Fe3GeTe2

Author

Zhang, Luman, primary, Song, Luyao, additional, Dai, Hongwei, additional, Yuan, Jun-Hui, additional, Wang, Mingshan, additional, Huang, Xinyu, additional, Qiao, Lei, additional, Cheng, Hui, additional, Wang, Xia, additional, Ren, Wei, additional, Miao, Xiangshui, additional, Ye, Lei, additional, Xue, Kan-Hao, additional, and Han, Jun-Bo, additional

Published
2020
Full Text
View/download PDF

28. Dynamic Magnetic and Optical Insight into a High Performance Pentagonal Bipyramidal Dy(III) Single-Ion Magnet

Author

Chen, Yan-Cong, Liu, Jun-Liang, Lan, Yanhua, Zhong, Zhi-Qiang, Mansikkamäki, Akseli, Ungur, Liviu, Li, Quan-Wen, Jia, Jian-Hua, Chibotaru, Liviu F., Han, Jun-Bo, Wernsdorfer, Wolfgang, Chen, Xiao-Ming, and Tong, Ming-Liang

Subjects
molecular magnets, single-molecule magnets, dynamic magnetic measurements
Abstract

The pentagonal bipyramidal single-ion magnets (SIMs) are among the most attractive prototypes of high-performance single-molecule magnets (SMMs). Here, a fluorescence-active phosphine oxide ligand CyPh2PO (=cyclohexyl(diphenyl)phosphine oxide) was introduced into [Dy(CyPh2PO)2(H2O)5]Br3⋅2 (CyPh2PO)⋅EtOH⋅3 H2O, and combined dynamic magnetic measurement, optical characterization, ab initio calculation, and magneto-optical correlation of this high-performance pseudo-D5h DyIII SIM with large Ueff (508(2) K) and high magnetic hysteresis temperature (19 K) were performed. This work provides a deeper insight into the rational design of promising molecular magnets. peerReviewed

Published
2017

29. Enhancement of the Coercive Field and Exchange Bias Effect in Fe3GeTe2/MnPX3(X = S and Se) van der Waals Heterostructures

Author

Dai, Hongwei, Cheng, Hui, Cai, Menghao, Hao, Qinghua, Xing, Yuntong, Chen, Hongjing, Chen, Xiaodie, Wang, Xia, and Han, Jun-Bo

Abstract

Fe3GeTe2/MnPS3and Fe3GeTe2/MnPSe3van der Waals heterostructures were fabricated by mechanical exfoliation. Via the magneto-optical Kerr effect and reflected magnetic circular dichroism measurements, we have observed nearly three times enhancement of the coercive field, improvement of Curie temperature, and exchange bias effect in both heterostructures. These observations may provide new insights into the emergent heterostructure devices between itinerant ferromagnets and metal thio- and selenophosphates for both applied and fundamental research studies in magnetic correlations.

Published
2021
Full Text
View/download PDF

37. Dynamic Magnetic and Optical Insight into a High-Performance Pentagonal Bipyramidal DyIII Single-Ion Magnet

Author

Chen, Yan-Cong, primary, Liu, Jun-Liang, additional, Lan, Yanhua, additional, Zhong, Zhi-Qiang, additional, Mansikkamäki, Akseli, additional, Ungur, Liviu, additional, Li, Quan-Wen, additional, Jia, Jian-Hua, additional, Chibotaru, Liviu F., additional, Han, Jun-Bo, additional, Wernsdorfer, Wolfgang, additional, Chen, Xiao-Ming, additional, and Tong, Ming-Liang, additional

Published
2017
Full Text
View/download PDF

39. Metasurfaces Composed of Plasmonic Molecules: Hybridization Between Parallel and Orthogonal Surface Lattice Resonances.

Author

Liu, Shao‐Ding, Yue, Peng, Zhang, Shi, Wang, Mingshan, Dai, Hongwei, Chen, Yiqin, Nie, Zhong‐Quan, Cui, Yanxia, Han, Jun‐Bo, and Duan, Huigao

Subjects
ORTHOGONAL surfaces, POLARITONS, RESONANCE, HYBRID materials, DELOCALIZATION energy, MOLECULES
Abstract

Multiple surface lattice resonances suppress radiative losses effectively around several spectral positions, thereby enhancing the light‐matter interactions and making them promising for multiwavelength related applications, and it is important to develop reliable methods to generate multiple lattice resonances. In analogy to natural materials composed of various kinds of molecules, this study proposed to construct metasurfaces with plasmonic artificial molecules, which represent distinct collective responses compared with that of single nanoparticles. It is shown that sharp multiple surface lattice resonances are excited due to the coupling between the localized resonances of plasmonic trimer molecules and the Rayleigh anomalies of the array, and there is a rarely observed parallel lattice resonance caused by the formation of equivalent dipoles perpendicular to the polarization. Particularly, even though the parallel mode is weak, a pronounced anticrossing behavior due to the hybridization with the orthogonal mode occurs when the resonance energies are approaching to each other, which results in two hybridized eigenmodes that possess both characteristics of parallel and orthogonal Rayleigh anomalies. Considering the excitation of the lattice resonances in asymmetric environments, the flexible tunability, and the ability to tailor the collective responses, metasurfaces constructed with artificial molecules are promising platforms to design ultrafast and compact photonic devices. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

40. One- and Two-Photon Excited Fluorescence of CdSe and CdSe/ZnS Quantum Dots in n-Hexane

Author

Wang Qu-Quan, Hao Zhong-Hua, Gong Hong-Mei, Zhai Yue-Ying, and Han Jun-Bo

Subjects
Nonlinear absorption, Materials science, Passivation, Condensed Matter::Other, Physics::Optics, General Physics and Astronomy, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Photochemistry, Fluorescence, Hexane, Condensed Matter::Materials Science, chemistry.chemical_compound, Two-photon excitation microscopy, chemistry, Quantum dot, Excited state, Absorption (electromagnetic radiation)
Abstract

One- and two-photon absorption and excited fluorescence of the CdSe and the core-shell structure CdSe/ZnS quantum dots (QDs) in n-hexane is investigated. The linear and nonlinear absorption coefficients are measured and the two-photon-absorption cross sections of the QDs are also obtained. For both one-photon fluorescence and two-photon fluorescence, the emission efficiency of CdSe/ZnS is much higher than that of CdSe, originating from the effective surface passivation of the core-shell structure.

Published
2006
Full Text
View/download PDF

42. A Sign Alternation of Nonlinear Absorption in Gold Composite Films in Z-Scan

Author

Xiao Si, Han Jun-Bo, Wang Qu-Quan, Ding Sha, Zhou Hui-Jun, Chen Dai-Jian, and Xiong Gui-guang

Subjects
Optical nonlinearity, Nonlinear absorption, Materials science, Reverse saturable absorption, Femtosecond, Composite number, Analytical chemistry, Alternation (geometry), General Physics and Astronomy, Z-scan technique, Atomic physics, Saturation (magnetic)
Abstract

Au–TiO2 composite films with Au atom content varying from about 15% to 82% are prepared by co-sputtering technique. Both open- and closed-aperture Z-scan of the samples are performed in the femtosecond time region. A conversion of the nonlinear absorption from negative to positive is observed as the Au atom content increases due to the saturation of reverse saturable absorption. The nonlinear refractive index γ and effective nonlinear absorption coefficient βeff at the Au atom content of 54% are measured to be 1.6×10−2 cm2/GW and −2.6×103 cm/GW, respectively. The corresponding third-order optical nonlinearity χ(3) is about 6.3×10−8 esu.

Published
2005
Full Text
View/download PDF

43. Cover Picture: Dynamic Magnetic and Optical Insight into a High Performance Pentagonal Bipyramidal DyIII Single-Ion Magnet (Chem. Eur. J. 24/2017)

Author

Chen, Yan-Cong, primary, Liu, Jun-Liang, additional, Lan, Yanhua, additional, Zhong, Zhi-Qiang, additional, Mansikkamäki, Akseli, additional, Ungur, Liviu, additional, Li, Quan-Wen, additional, Jia, Jian-Hua, additional, Chibotaru, Liviu F., additional, Han, Jun-Bo, additional, Wernsdorfer, Wolfgang, additional, Chen, Xiao-Ming, additional, and Tong, Ming-Liang, additional

Published
2017
Full Text
View/download PDF

46. Gap-Induced Giant Third-Order Optical Nonlinearity and Long Electron Relaxation Time in Random-Distributed Gold Nanorod Arrays

Author

Wang, Xia, Yao, Linhua, Chen, Xiaodie, Dai, Hongwei, Wang, Mingshan, Zhang, Luman, Ni, Yun, Xiao, Lixia, and Han, Jun-Bo

Abstract

The third-order optical nonlinearities and the hot electron relaxation time (τ) of random-distributed gold nanorods arrays on glass (R-GNRA) have been investigated by using Z-scan and optical Kerr effect (OKE) techniques. Large third-order optical susceptibility (χ(3)) with the value of 2.5 × 10–6esu has been obtained around the plamsonic resonance peak under the excitation power intensity of 0.1 GW/cm2. Further decrease of the excitation power intensity down to 0.3 MW/cm2will lead to the significant increase of χ(3)up to 6.4 × 10–4esu. The OKE results show that the relaxation time of R-GNRA around the plasmonic peak is 13.9 ± 0.4 ps, which is more than 4 times longer than those of the individual gold nanostructures distributed in water solutions. The Finite-difference time domain simulations demonstrate that this large enhancement of χ(3)and slow down of τ are caused by the gap-induced large local field enhancement of GNRs dimers in R-GNRA. These significant results offer great opportunities for plasmonic nanostructures in applications of photonic and photocatalytic devices.

Published
2024
Full Text
View/download PDF

47. Ultrafast Third-Order Optical Nonlinearity in Au Triangular Nanoprism with Strong Dipole and Quadrupole Plasmon Resonance

Author

Li, Zixuan, Yu, Ying, Chen, Ziyu, Liu, Tianran, Zhou, Zhang-Kai, Han, Jun-Bo, Li, Juntao, Jin, Chongjun, and Wang, Xuehua

Abstract

Au triangular nanoprisms have been prepared by the wet chemical method. By using absorption measurements and finite difference time domain (FDTD) calculations, the dipole and quadrupole plasmon resonances of Au triangular nanoprisms are investigated experimentally and theoretically. Calculations show that large electric fields are confined at the tips of the Au prisms, leading to large third-order optical nonlinearities. The Z-scan measurements show a third-order optical susceptibility of about 1.25 × 10–11esu at 1240 nm, which is 19 times larger than that at 800 nm. The ultrafast light response time is about 482 fs measured by optical Kerr effect technique at 800 nm. The distinct third-order optical nonlinearities and the ultrafast response time enable the Au triangular prisms to be a good candidate for future all-optical switches and ultrafast optical information manipulators.

Published
2024
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results