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Mechanical-electro-Magnetic coupling in strained bilayer CrI3

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Science China(Technological Sciences) 2020年第7期63卷 1265-1271页

作者： ZHANG ShuQing ZOU XiaoLong CHENG HuiMing Shenzhen Geim Graphene Center(SGC) Tsinghua-Berkeley Shenzhen Institute(TBSI)&Tsinghua Shenzhen International Graduate School(TSIGS)Tsinghua UniversityShenzhen 518055China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The discovery of intrinsic 2D ferromagnets provides exciting possibilities for spintronics applications. A particularly attractive example is CrI3, whose monolayer is ferromagnetic while bilayer shows antiferroMagnetic coupling. Because of weak interlayer coupling, the magnetism of bilayer CrI3 can be easily modulated by external perturbations, such as gating or pressure. Here, we constructed a magnetic phase diagram of bilayer CrI3 under arbitrary biaxial strain(within ±4%) from compression to stretch,and found that compressive strain can effectively convert the antiferroMagnetic coupling of bilayer CrI3 to ferromagnetic.Detailed analyses on electronic structure were then performed to unravel the underlying mechanism of the magnetic phase transition. It was shown that both band gap and orbital composition at conduction band minimum play important roles in determining magnetic ground states of strained bilayer CrI3. These results strengthen our understanding of the interlayer magnetism of 2D magnets and provide a feasible way to modulate the magnetism in 2D layered materials.

关键词： bilayer Crl3 Magnetic coupling strain band gap orbital composition

Magnetic coupling engineered porous dielectric carbon within ultralow filler loading toward tunable and high-performance microwave absorption

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Journal of Materials Science & Technology 2021年第11期70卷 214-223页

作者： Wang Yang Bo Jiang Zhihui Liu Rui Li Liqiang Hou Zhengxuan Li Yongli Duan Xingru Yan Fan Yang Yongfeng Li State Key Laboratory of Heavy Oil Processing China University of Petroleum(Beijing)Changping 102249China

Developing microwave absorption(MA)materials with satisfied comprehensive performance is a great challenge for tackling severe electromagnetic pollution.In particular,the magnetic component/carbon hybrids absorbers always suffer from high filler loading.Herein,we propose a feasible strategy to construct hierarchical porous carbon with tightly embedded Ni nanoparticles(Ni@NPC).These highly dispersed Ni nanoparticles produce strong Magnetic coupling networks to enhance magnetic loss abilities.Moreover,the interconnected hierarchical dielectric carbon network affords favorable dipolar/interfacial polarization,conduction loss,multiple reflection and scattering.Impressively,with an ultralow filler loading of 5 wt.%,the resultant Ni@NPC/paraffin composite achieves an excellent MA performance with a minimum reflection loss of as high as-72.4 dB and a broad absorption bandwidth of 5.0 GHz.This capability outperforms most current magnetic-dielectric hybrids counterparts.Furthermore,the MA capacity can be easily tuned with adjustments in thickness,content and type of magnetic material.Thus,this work opens up new avenues for the development of high-performance and lightweight MA materials.

关键词： Hierarchical porous carbon magnetic nanoparticles Magnetic coupling Ultralow filler loading High-performance microwave absorption

Tunable electronic structure and Magnetic coupling in strained two-dimensional semiconductor MnPSe3

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Frontiers of physics 2018年第4期13卷 167-174页

作者： Qi Pei Xiao-Cha Wang Ji-Jun ZOU Wen-Bo Mi Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology School of Science Tianjin University Tianjin 300354 China School of Electrical and Electronic Engineering Tianjin University of Technology Tianjin 300384 China Key Laboratory for Green Chemical Technology of the Ministry of Education School of Chemical Engineering and Technology Tianjin University Tianjin 300354 China

The electronic structures and magnetic properties of strained monolayer MnPSe3 are investigated sys- tematically via first-principles calculations. It is found that the magnetic ground state of monolayer MnPSe3 can be significantly affected by biaxial strain engineering, while the semiconducting char- acteristics are well-preserved. Owing to the sensitivity of the Magnetic coupling towards structural deformation, a biaxial tensile strain of approximately 13% can lead to an antiferromagnetic （AFM）- ferromagnetic （FM） transition. The strain-dependent magnetic stability is mainly attributed to the competition of the direct AFM interaction and indirect FM superexchange interaction between the two nearest-neighbor Mn atoms. In addition, we find that FM MnPSe3 is an intrinsic half semiconductor with large spin exchange splitting in the conduction bands, which is crucial for the spin-polarized carrier injection and detection. The sensitive interdependence among the external stimuli, electronic structure, and Magnetic coupling makes monolayer MnPSe3 a promising candidate for spintronics.

关键词： two-dimensional semiconductor MnPSe3 strain engineering electronic structure Magnetic coupling

Broadband energy harvesting via Magnetic coupling between two movable magnets

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Chinese Physics B 2014年第8期23卷 374-381页

作者：樊康旗徐春辉王卫东方阳 School of Electronical & Mechanical Engineering Xidian University

Harvesting energy from ambient mechanical vibrations by the piezoelectric effect has been proposed for powering microelectromechanical systems and replacing batteries that have a finite life span. A conventional piezoelectric energy harvester （PEH） is usually designed as a linear resonator, and suffers from a narrow operating bandwidth. To achieve broadband energy harvesting, in this paper we introduce a concept and describe the realization of a novel nonlinear PEH. The proposed PEH consists of a primary piezoelectric cantilever beam coupled to an auxiliary piezoelectric cantilever beam through two movable magnets. For predicting the nonlinear response from the proposed PEH, lumped parameter models are established for the two beams. Both simulation and experiment reveal that for the primary beam, the introduction of Magnetic coupling can expand the operating bandwidth as well as improve the output voltage. For the auxiliary beam, the magnitude of the output voltage is slightly reduced, but additional output is observed at off-resonance frequencies. Therefore, broadband energy harvesting can be obtained from both the primary beam and the auxiliary beam.

关键词： piezoelectric conversion mechanical vibration Magnetic coupling energy harvesting

π-π Stacking, Hydrogen Bonding and Magnetic coupling Mechanism on a Mono-nuclear Cu^Ⅱ Complex

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Chinese Journal of Structural Chemistry 2012年第2期31卷 285-291页

作者：李红于丽张士国王玉清石敬民 Binzhou Key Laboratory of Material Chemistry Department of Chemistry and Chemical EngineeringBinzhou University Department of Chemistry Shandong Normal University

A new mono-nuclear CuII complex [Cu（DPP）（DP）Br]（ClO4）H2O （DPP = 2-（3,5- dimethyl-1H-pyrazol-1-yl）-1,10-phenanthroline, DP = 3,5-dimethyl-1H-pyrazole） has been syn- thesized with 2-（3,5-dimethyl-1H-pyrazol-1-yl）-1,10-phenanthroline and 3,5-dimethyl-1H-pyrazole as ligands, and its crystal structure was determined by X-ray crystallography. The crystal is of monoclinic system, space group P21/c with a = 13.765（2）, b = 17.044（3）, c = 10.9044（16）, β= 97.112（2）°, V = 2538.5（6）3, Z = 4, C22H24BrClCuN6O5, Mr = 631.37, Dc = 1.652 g/cm3, F（000） = 1276 and μ= 2.585 mm-1. In the crystal, DPP functions as a tridentate ligand and CuII ions assume a distorted square pyramidal geometry with Br atom lying on the apex, and at the same time, there is π-π stacking between adjacent complexes, which deals with two 1,10-phenanthroline plane rings. In addition to the π-π stacking, there are C-H···Br non-classic hydrogen bonds between adjacent complexes. The theoretical calculations reveal that the π-π stacking and C-H···Br non-classic hydrogen bond result in a weak anti-ferromagnetic interaction with 2J = -5.34 cm-1 and a weak ferromagnetic 2J = 5.92 cm-1, respectively. The Magnetic coupling sign from the π-π stacking could be explained with McConnell I spin-polarization mechanism.

关键词： crystal structure Magnetic coupling π-π stacking hydrogen bond copper complex

Modeling and dynamics of double Hindmarsh-Rose neuron with memristor-based Magnetic coupling and time delay

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Chinese Physics B 2021年第12期30卷 102-110页

作者：齐国元王子谋 Tianjin Key Laboratory of Intelligent Control of Electrical Equimpment Tiangong UniversityTianjin 300387China

The firing of a neuron model is mainly affected by the following factors:the magnetic field,external forcing current,time delay,etc.In this paper,a new time-delayed electromagnetic field coupled dual Hindmarsh-Rose neuron network model is constructed.A magnetically controlled threshold memristor is improved to represent the self-connected and the coupled magnetic fields triggered by the dynamic change of neuronal membrane potential for the adjacent neurons.Numerical simulation confirms that the coupled magnetic field can activate resting neurons to generate rich firing patterns,such as spiking firings,bursting firings,and chaotic firings,and enable neurons to generate larger firing amplitudes.The study also found that the strength of Magnetic coupling in the neural network also affects the number of peaks in the discharge of bursting firing.Based on the existing medical treatment background of mental illness,the effects of time lag in the coupling process against neuron firing are studied.The results confirm that the neurons can respond well to external stimuli and coupled magnetic field with appropriate time delay,and keep periodic firing under a wide range of external forcing current.

关键词： bi-Hindmarsh and Rose(HR)neuron model memristor Magnetic coupling time delay

Development of a low-loss magnetic-coupling pickup for 166.6-MHz quarter-wave beta=1 superconducting cavities

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Nuclear Science and Techniques 2020年第9期31卷 25-32页

作者： Tong-Ming Huang Pei Zhang Zhong-Quan Li Xin-Ying Zhang Hai-Ying Lin Qiang Ma Fan-Bo Meng Wei-Min Pan Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Key Laboratory of Particle Acceleration Physics and Technology IHEPCASBeijing 100049China School of Nuclear Sciences and Technology University of Chinese Academy of SciencesBeijing 100049China

166.6-MHz quarter-waveβ=1 superconducting cavities have been adopted for the High Energy Photon Source,a 6-GeV diffraction-limited synchrotron light source currently under construction.A large helium jacket was required to accommodate the enlarged cavity beam pipe for the heavy damping of higher-order modes;the original electric-probe pickup thus becomes inevitably long with unfavorable mechanical properties.Relocated to an existing high-pressure-rinsing port,a magnetic-loop pickup was designed,characterized by low radio-frequency and cryogenic losses and being multipacting-free and insensitive to manufacturing and assembly tolerances.The consequent removal of the original pickup port from the cavity largely simplified the helium jacket fabrication and may also reduce cavity contamination.This paper presents a comprehensive design of a low-loss magnetic-coupling pickup for quarter-waveβ=1 superconducting cavities.The design can also be applied to other non-elliptical structures.

关键词： Pickup Magnetic coupling Quarter-wave cavity Superconducting cavity Low loss Synchrotron light source

π-π Stacking and Magnetic coupling Mechanism on a Mono-nuclear Mn(Ⅱ) Complex

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Chinese Journal of Structural Chemistry 2011年第12期30卷 1751-1757页

作者：陈虎刘利真马艳杜华石敬民 College of Chemistry Chemical Engineering and Materials ScienceKey Laboratory of Molecular and Nano ProbesEngineering Research Center of Pesticide and Medicine Intermediate Clean ProductionMinistry of EducationShandong Provincial Key Laboratory of Clean Production of Fine ChemicalsShandong Normal University School of Pharmacy Shandong University of Traditional Chinese Medicine

A new mono-nuclear Mn（Ⅱ） complex [Mn（MPT）2（NCS）（HOCH3）]ClO4（MPT = 2-methoxyl-1,10-phenanthroline） has been synthesized with 2-methoxyl-1,10-phenanthroline and thiocyanate anion as ligands,and its crystal structure was determined by X-ray crystallography.The crystal data：monoclinic system,space group P21/c with a = 12.8849（17）,b = 15.684（2）,c = 14.2703（19） ,β = 92.126（2）°,V = 2881.9（7） 3,Z = 4,C28H24ClMnN5O7S,Mr = 664.97,Dc = 1.533 g/cm3,F（000） = 1364 and μ = 0.679 mm-1.In the crystal,MPT functions as a bidentate ligand and Mn（Ⅱ） ion assumes a distorted octahedral geometry.In the crystal there are two types of π-π stacking interactions among the adjacent complexes,which involves 1,10-phenanthroline rings.The theoretical calculations reveal that the two types of π-π stacking resulted in a weak anti-ferroMagnetic coupling with 2J =-14.68 cm-1 and a weak ferroMagnetic coupling with 2J = 0.70 cm-1,respectively.The theoretical calculations also reveal that there are both spin polarization and spin delocalization in the two π-π stacking systems,and the Magnetic coupling signs are unable to explain with McConnell I spin-polarization mechanism.

关键词： crystal structure Magnetic coupling π-π stacking theoretical calculation manganese complex

Magnetic coupling in La_(0.67)Ca_(0.33)MnO_3/La_(0.67)Sr_(0.33)CoO_3/La_(0.67)Ca_(0.33)MnO_3 Trilayer Films

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Journal of Rare Earths 2004年第6期22卷 887-890页

作者：赵昆李昊黄康权 Magnetoelectronics Laboratory School of Physics Science and Information Technology Liaocheng University Department of Physics Chinese University of Hong Kong Hong Kong 00852 China

The perovskite La_(0.67)Ca_(0.33)MnO_3/La_(0.67)Sr_(0.33)CoO_3/La_(0.67)Ca_(0.33)MnO_3 trilayers were fabricated by a facing-target sputtering technique and their magnetotransport properties were investigated. The magnetoresistance is dependent on spacer thickness and dramatically decreases when La_(0.67)Sr_(0.33)CoO_3 layer is thick enough because of its short-circuiting effect. Different from La_(0.67)Ca_(0.33)MnO_3 single layer, trilayer films with thin La_(0.67)Sr_(0.33)CoO_3 spacer have the enhanced metal-semiconductor transition temperature (T_(MS)) of La_(0.67)Ca_(0.33)MnO_3 layers. The magnetic coercivity H_C shows a nonmonotonic behavior with changing the spacer layer thickness at 230 K. The waist-like hysteresis indicates that there is an indirect exchange coupling between the top and bottom La_(0.67)Ca_(0.33)MnO_3 layers across the spacer La_(0.67)Sr_(0.33)CoO_3 layer.

关键词： colossal magnetoresistance hysteresis loop Magnetic coupling rare earths