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Electrically function-switchable magnetic domain-wall memory

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National Science Review 2023年第10期10卷 72-78页

作者： Yu Sheng Weiyang wang Yongcheng Deng Yang Ji Houzhi Zheng kaiyou wang State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of Sciences College of Materials Science and Opto-Electronic Technology University of Chinese Academy of Sciences

Versatile memory is strongly desired for end users,to protect their information in the information era.In particular,bit-level switchable memory that can be switched from rewritable to read-only function would allow end users to prevent important data being tampered with.However,no such switchable memory has been reported.We demonstrate that the rewritable function can be converted into read-only function by applying a sufficiently large current pulse in a U-shaped domain-wall memory,which comprises an asymmetric Pt/Co/Ru/AlOxheterostructure with strong D zyaloshinskii-Moriya interaction.Wafer-scale switchable magnetic domain-wall memory arrays on 4-inch Si/SiO2substrate are demonstrated.Furthermore,we confirm that the information can be stored in rewritable or read-only states at bit level according to the security needs of end users.Our work not only provides a solution for personal confidential data,but also paves the way for developing multifunctional spintronic devices.

关键词： spintronics spin orbit torques magnetic domain-wall SOT-MRAM information security

All-electrical switching of a topological non-collinear antiferromagnet at room temperature

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National Science Review 2023年第2期10卷 123-130页

作者： Yongcheng Deng Xionghua Liu Yiyuan Chen Zongzheng Du Nai Jiang Chao Shen Enze Zhang Houzhi Zheng Hai-Zhou Lu kaiyou wang State Key Laboratory for Superlattices and Microstructures Institute of SemiconductorsChinese Academy of Sciences Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Institute for Quantum Science and Engineering and Department of Physics Southern University of Science and Technology (SUSTech) International Quantum Academy Beijing Academy of Quantum Information Sciences Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences

Non-collinear antiferromagnetic Weyl semimetals,combining the advantages of a zero stray field and ultrafast spin dynamics,as well as a large anomalous Hall effect and the chiral anomaly of Weyl fermions,have attracted extensive interest.However,the all-electrical control of such systems at room temperature,a crucial step toward practical application,has not been reported.Here,using a small writing current density of around 5 × 106A·cm-2,we realize the all-electrical current-induced deterministic switching of the non-collinear antiferromagnet Mn3Sn,with a strong readout signal at room temperature in the Si/SiO2/Mn3Sn/AlOxstructure,and without external magnetic field or injected spin current.Our simulations reveal that the switching originates from the current-induced intrinsic non-collinear spin-orbit torques in Mn3Sn itself.Our findings pave the way for the development of topological antiferromagnetic spintronics.

关键词： spintronics non-collinear antiferromagnetic Weyl semimetals all-electrical switching spin-orbit torques

Giant Magneto-Optical Effect in van der Waals Room-Temperature Ferromagnet Fe_(3)GaTe_(2)

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Chinese Physics Letters 2024年第6期41卷 148-155页

作者：张晓敏王健朱文凯张佳茜李伟浩张菁王开友 State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China School of Materials Shenzhen Campus of Sun Yat-sen UniversityShenzhen 518107China

The discovery of ferromagnetic two-dimensional(2D)van der Waals(vdWs)materials provides an opportunity to explore intriguing physics and to develop innovative spin electronic devices.However,the main challenge for practical applications of vd Ws ferromagnetic crystals lies in the weak intrinsic ferromagnetism and small perpendicular magnetic anisotropy(PMA)above room temperature.Here,we report the intrinsic vd Ws ferromagnetic crystal Fe_(3)GaTe_(2),synthesized by the self-flux method,exhibiting a Curie temperature(TC)of 370 K,a high saturation magnetization of 33.47 emu/g,and a large PMA energy density of approximately 4.17×10^(5)J/m^(3).Furthermore,the magneto-optical effect is systematically investigated in Fe_(3)GaTe_(2).The doubly degenerate E_(2g)(Γ)mode reverses the helicity of incident photons,indicating the existence of pseudoangular-momentum(PAM)and chirality.Meanwhile,the non-degenerate non-chiral A_(1g)(Γ)phonon exhibits a significant magneto-Raman effect under an external out-of-plane magnetic field.These results lay the groundwork for studying phonon chirality and magneto-optical phenomena in 2D magnetic materials,providing the feasibility for further fundamental research and applications in spintronic devices.

关键词： field. ferromagnetic degenerate

Large Room-Temperature Magnetoresistance in van der Waals Ferromagnet/Semiconductor Junctions

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Chinese Physics Letters 2022年第12期39卷 99-103页

作者： Wenkai Zhu Shihong Xie Hailong Lin Gaojie Zhang Hao Wu Tiangui Hu Ziao wang Xiaomin Zhang Jiahan Xu Yujing wang Yuanhui Zheng Faguang Yan Jing Zhang Lixia Zhao Amalia Patanè Jia Zhang Haixin Chang kaiyou wang State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China School of Physics and Astronomy University of NottinghamNottingham NG72RDUnited Kingdom Center for Joining and Electronic Packaging State Key Laboratory of Material Processing and Die&Mold TechnologySchool of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China Wuhan National High Magnetic Field Center Huazhong University of Science and TechnologyWuhan 430074China School of Electrical and Electronic Engineering Tiangong UniversityTianjin 300387China School of Physics Huazhong University of Science and TechnologyWuhan 430074China

A magnetic tunnel junction(MTJ)is the core component in memory technologies,such as the magnetic random-access memory,magnetic sensors and programmable logic devices.In particular,MTJs based on twodimensional van der Waals(vd W)heterostructures offer unprecedented opportunities for low power consumption and miniaturization of spintronic devices.However,their operation at room temperature remains a challenge.Here,we report a large tunnel magnetoresistance(TMR)of up to 85%at room temperature(T=300 K)in vdW MTJs based on a thin(<10 nm)semiconductor spacer WSe_(2)layer embedded between two Fe_(3)GaTe_(2e)lectrodes with intrinsic above-room-temperature ferromagnetism.The TMR in the MTJ increases with decreasing temperature up to 164%at T=10 K.The demonstration of TMR in ultra-thin MTJs at room temperature opens a realistic and promising route for next-generation spintronic applications beyond the current state of the art.

关键词： resistance spacer tunnel

Oscillation of current-induced interfacial spins reorientation in a like-synthetic antiferromagnet/antiferromagnet system

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Science China(Physics,Mechanics & Astronomy) 2021年第6期64卷 106-113页

作者： XiongHua Liu YongCheng Deng XiuKai Lan RunZe Li kaiyou wang State Key Laboratory for Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Beijing Academy of Quantum Information Sciences Beijing 100193China Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100049China

Antiferromagnets have been attracting tremendous interest in the spintronics community due to their intrinsic appealing properties,such as zero stray field and ultrafast spin dynamics.Recently,the electrical manipulation of bulk properties of antiferromagnets has been widely studied,but exploring the use of antiferromagnetic(AFM)interfacial properties to investigate some key issues in spintronic devices is urgently desired.In this study,the magnetic and spin transport properties mediated by interlayer exchange coupling(IEC)are examined through spin-orbit torque(SOT)-induced tunability of interfacial spins in heavy-metal/like-synthetic antiferromagnet/antiferromagnet heterostructure devices.We found that the exchange bias and coercivity and the critical current density for SOT switching can be modulated by IEC,associating with the oscillation of SOTinduced interfacial spins reorientation at zero field,which can be well understood with the modified Ruderman-Kittel-KasuyaYosida model.Our finding opens a new route for understanding and using the AFM interfacial spins in spintronics.

关键词： spintronics antiferromagnetic interfacial spins spin-orbit torque oscillation

Assessment of tree-ring mercury radial translocation and age effect in Masson pine:Implications for historical atmospheric mercury reconstruction

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Journal of Environmental Sciences 2024年第4期138卷 266-276页

作者： Xu Liu Xun wang Dingyong wang College of Resources and Environment Southwest UniversityChongqing 400715China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

The tree ring has been regarded as an emerging archive to reconstruct historical atmospheric mercury(Hg)trends,but with the large knowledge gaps in the reliability.In this study,we comprehensively evaluated the Hg source,radial translocation and age effect of Masson pine(Pinus massoniana)tree ring at Mt.Jinyun in Chongqing,to assess the suitability of such tree ring as the archive of atmospheric Hg.Results showed that distinct variabilities among Masson pine tree-ring Hg concentration profiles.The Hg concentration significantly increased along with stem height(P<0.05),indicating the Hg in tree rings mainly derived from foliage uptake atmospheric Hg.We found a distinct age effect that the tree ring of young trees had the higher Hg concentration.Besides,we used the advection-diffusion model to demonstrate how Hg concentration shifted by the advection or/and diffusion in tree rings.The modeling results showed that the advection induced radial translocation during the young growth period of tree was a plausible mechanism to result in the tree-ring Hg record largely different from the trend of anthropogenic Hg emissions in Chongqing.We finally suggest that in further Hg dendrochemistry,better discarding the tree-ring Hg profile of the young growth period to reduce impacts of the radial translocation and age effect.

关键词： Masson pine Tree-ring mercury Radial translocation Tree age effect

Pushing the boundaries: an interview with Dae-Hyun Kim on terahertz devices

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National Science Review 2024年第3期11卷 42-45页

作者： Defu wang the Center for Carbon-based Electronics School of Electronics Peking University

Ⅲ–Ⅴ compound semiconductors, such as InGaAs/InAlAs, exhibit exceptional carrier transport properties, establishing them as fundamental elements in terahertz(THz) applications crucial for the development of 6G netwo...

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Enrichment of anammox biomass during mainstream wastewater treatment driven by achievement of partial denitrification through the addition of bio-carriers

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Journal of Environmental Sciences 2024年第3期137卷 181-194页

作者： Yuqing Ma Bo wang Xiaodi Li Shuo wang Wen wang Yongzhen Peng National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology Engineering Research Center of BeijingBeijing University of TechnologyBeijing 100124China

Anammox is widely considered as the most cost-effective and sustainable process for nitrogen removal.However,how to achieve the enrichment of anammox biomass remains a challenge for its large-scale application,especially in mainstream wastewater treatment.In this study,the feasibility of enrichment of anammox biomass was explored through the realization of partial denitrification and the addition of bio-carriers.By using ordinary activated sludge,a sequencing batch reactor(SBR)followed by an up-fow anaerobic sludge bed(UASB)was operated at 25±2℃ for 214 days.The long-term operation was divided into five phases,in which SBR and UASB were started-up in Phases I and II,respectively.By eliminating oxygen and adjusting the infow ratios in Phases III-V,advanced nitrogen removal was achieved with the effuent total nitrogen being 4.7 mg/L and the nitrogen removal efficiency being 90.5%in Phase V.Both in-situ and ex-situ activity tests demonstrated the occurrence of partial denitrification and anammox.Moreover,16S rRNA high-throughput sequencing analysis revealed that Candidatus Brocadia was enriched from below the detection limit to in biofilms(0.4%in SBR,2.2%in UASB)and the foc sludge(0.2%in SBR,1.3%in UASB),while Thauera was mainly detected in the foc sludge(8.1%in SBR,8.8%in UASB),which might play a key role in partial denitrification.Overall,this study provides a novel strategy to enrich anammox biomass driven by rapid achievement of partial denitrification through the addition of bio-carriers,which will improve large-scale application of anammox processes in mainstream wastewater treatment.

关键词： Enrichment Anammox biomass Bio-carriers Partial denitrification Mainstream wastewater

Performance and mechanism of La-Fe metal-organic framework as a highly efficient adsorbent for fluoride removal from mine water

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Journal of Environmental Sciences 2024年第5期139卷 245-257页

作者： Chaomin Jia Jianbing wang Huijiao wang Sichao Zhu Xiaohui Zhang Yuxiang wang School of Chemical&Environmental Engineering China University of Mining&Technology-BeijingBeijing 100083China Beijing Polytechnic Beijing 100176China Chinese Society for Urban Studies Beijing 100835China

Water fluoride pollution has caused non-negligible harm to the environment and humans,and thus it is crucial to find a suitable treatment technology.In this study,La-Fe@PTA adsorbent was synthesized for the defluoridation of mine water.The results showed that the optimum conditions for defluoridation by La-Fe@PTA were p H close to 7.0,the initial F-concentration of 10 mg/L,the dosage of 0.5 g/L and the adsorption time of 240 min.Compared with SO_4^(2-),Cl^(-),NO_(3)^(-),Ca^(2+)and Mg^(2+),CO_(3)^(2-)and HCO_(3)^(-)presented severer inhibition on fluoride uptake by La-Fe@PTA.The adsorption process fits well with the pseudo-second-order kinetic model and Freundlich model,and the maximum adsorption capacity of Langmuir model was 95 mg/g.Fixed-bed adsorption results indicated that fluoride in practical fluorinated mine water could be effectively removed from 3.6 mg/L to less than 1.5 mg/L within130 bed volume(BV)by using 1.5 g La-Fe@PTA.Furthermore,the adsorbent still had good adsorption capacity after regeneration,which confirms the great application potential of La-Fe@PTA as a fluoride ion adsorbent.The mechanism analysis showed that La-Fe@PTA adsorption of fluorine ions is a physicochemical reaction driven by electrostatic attraction and ion exchange.

关键词： Adsorption La-Fe@PTA Fluoride ion Mine water Mechanism