Since Sep.2018,LAMOST has started the medium-resolution(R~7500)spectral survey(MRS).We proposed the spectral survey of Galactic nebulae,including HⅡregions,HH objects,supernova remnants,planetary nebulae and the spec...Since Sep.2018,LAMOST has started the medium-resolution(R~7500)spectral survey(MRS).We proposed the spectral survey of Galactic nebulae,including HⅡregions,HH objects,supernova remnants,planetary nebulae and the special stars with MRS(LAMOST MRS-N).LAMOST MRS-N covers about 1700 square degrees of the northern Galactic plane within 40°<l<215°and-5°<b<5°.In this 5-year survey,we plan to observe about 500 thousand nebulae spectra.According to the commissioning observations,the nebulae spectra can provide precise radial velocity with uncertainty less than 1 km s^(-1).These high-precision spectral data are of great significance to our understanding of star formation and evolution.展开更多
The heating and helicity effects induced by circularly polarized laser excitation are entangled in the helicity-dependent all-optical switching(HD-AOS),which hinders understanding the magnetization dynamics involved.H...The heating and helicity effects induced by circularly polarized laser excitation are entangled in the helicity-dependent all-optical switching(HD-AOS),which hinders understanding the magnetization dynamics involved.Here,applying a dual-pump laser excitation,first with a linearly polarized(LP) laser pulse followed by a circularly polarized(CP) laser pulse,the timescales and contribution from heating and helicity effects in HD-AOS were identified with a Pt/Co/Pt triple-layer.When the LP laser pulses preheat the sample to a nearly fully demagnetized state,the CP laser pulses with a power reduced by 80% switch the sample’s magnetization.By varying the time delay between the two pump pulses,the results show that the helicity effect,which gives rise to the deterministic helicity-induced switching,arises almost instantly within 200 fs close to the pulse width upon laser excitation.The results reveal that the transient magnetization state upon which CP laser pulses impinge is the key factor for achieving HD-AOS,and importantly,the tunability between heating and helicity effects with the unique dualpump laser excitation approach will enable HD-AOS in a wide range of magnetic material systems having wideranging implications for potential ultrafast spintronics applications.展开更多
Skyrmions, with their vortex-like structures and inherent topological protection, play a pivotal role in developing innovative low-power memory and logic devices. The efficient generation and control of skyrmions in g...Skyrmions, with their vortex-like structures and inherent topological protection, play a pivotal role in developing innovative low-power memory and logic devices. The efficient generation and control of skyrmions in geometrically confined systems are crucial for the development of skyrmion-based spintronic devices. In this study, we focus on investigating the non-reciprocal transport behavior of skyrmions and their interactions with boundaries of various shapes. The shape of the notch structure in the nanotrack significantly affects the dynamic behavior of magnetic skyrmions. Through micromagnetic simulation, the non-reciprocal transport properties of skyrmions in nanowires with different notch structures are investigated in this work.展开更多
Magnetic skyrmions are topological quasiparticles with nanoscale size and high mobility,which have potential applications in information storage and spintronic devices.The manipulation of skyrmion’s dynamics in the t...Magnetic skyrmions are topological quasiparticles with nanoscale size and high mobility,which have potential applications in information storage and spintronic devices.The manipulation of skyrmion’s dynamics in the track is an important topic due to the skyrmion Hall effect,which can deviate the skyrmions from the preferred direction.We propose a new model based on the ferromagnetic skyrmion,where the skyrmion velocity can be well controlled by adjusting the direction of the current.Using this design,we can avoid the annihilation of the skyrmion induced by the skyrmion Hall effect,which is confirmed by our micromagnetic simulation based on Mumax^(3).In the meantime,we increase the average velocity of the skyrmion by varying the intrinsic material parameters in the track,where the simulations agree well with our analytical results based on the Thiele equation.Finally,we give a phase diagram of the output of the skyrmion in the T-type track,which provides some practical ways for design of logic gates by manipulating crystalline anisotropy through the electrical control.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12073051,12090040,12090041,11733006,11403061,11903048,U1631131,11973060,12090044,12073039,11633009,U1531118,11403037,11225316,11173030,11303038,Y613991N01,U1531245,11833006)the Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences+4 种基金the Key Research Program of Frontier Sciences,CAS(Grant No.QYZDY-SSW-SLH007)the supports from the Science and Technology Development Fund,Macao SAR(file No.0007/2019/A)Faculty Research Grants of the Macao University of Science and Technology(No.FRG19-004-SSI)a National Major Scientific Project built by the Chinese Academy of SciencesFunding for the project has been provided by the National Development and Reform Commission。
文摘Since Sep.2018,LAMOST has started the medium-resolution(R~7500)spectral survey(MRS).We proposed the spectral survey of Galactic nebulae,including HⅡregions,HH objects,supernova remnants,planetary nebulae and the special stars with MRS(LAMOST MRS-N).LAMOST MRS-N covers about 1700 square degrees of the northern Galactic plane within 40°<l<215°and-5°<b<5°.In this 5-year survey,we plan to observe about 500 thousand nebulae spectra.According to the commissioning observations,the nebulae spectra can provide precise radial velocity with uncertainty less than 1 km s^(-1).These high-precision spectral data are of great significance to our understanding of star formation and evolution.
基金financially supported by the National Key Research and Development Program of China (No. 2016YFA0300803)the National Natural Science Foundation of China (Nos.61427812 and 11774160)+4 种基金the Natural ScienceFoundation of Jiangsu Province of China (No.BK20192006)support of National Key R&D Program of China (No.2021YFB3601600)the Natural Science Foundation of Jiangsu Province of China (No.BK20200307)support of the UK EPSRC (No.EP/T027916/1)supported by the EPSRC TER AS WITCH project (project ID EP/T027916/1)。
文摘The heating and helicity effects induced by circularly polarized laser excitation are entangled in the helicity-dependent all-optical switching(HD-AOS),which hinders understanding the magnetization dynamics involved.Here,applying a dual-pump laser excitation,first with a linearly polarized(LP) laser pulse followed by a circularly polarized(CP) laser pulse,the timescales and contribution from heating and helicity effects in HD-AOS were identified with a Pt/Co/Pt triple-layer.When the LP laser pulses preheat the sample to a nearly fully demagnetized state,the CP laser pulses with a power reduced by 80% switch the sample’s magnetization.By varying the time delay between the two pump pulses,the results show that the helicity effect,which gives rise to the deterministic helicity-induced switching,arises almost instantly within 200 fs close to the pulse width upon laser excitation.The results reveal that the transient magnetization state upon which CP laser pulses impinge is the key factor for achieving HD-AOS,and importantly,the tunability between heating and helicity effects with the unique dualpump laser excitation approach will enable HD-AOS in a wide range of magnetic material systems having wideranging implications for potential ultrafast spintronics applications.
基金Project supported by the Key-Area Research and Development Program of Guangdong Province,China(Grant No.2021B0101300003)the Guangdong Basic and Applied Basic Research Foundation,China(Grant Nos.2022A1515110863 and 2023A1515010837)+5 种基金the National Key Research and Development Program of China(Grant No.2016YFA0300803)the National Natural Science Foundation of China(Grant Nos.12304136,61427812,11774160,12241403,51771127,52171188,and 52111530143)the Natural Science Foundation of Jiangsu Province,China(Grant Nos.BK20192006 and BK20200307)the Fundamental Research Funds for the Central Universities,China(Grant No.021014380113)International Exchanges 2020 Cost Share(NSFC),China(Grant No.IECNSFC201296)the Project for Maiden Voyage of Guangzhou Basic and Applied Basic Research Scheme,China(Grant No.2024A04J4186)。
文摘Skyrmions, with their vortex-like structures and inherent topological protection, play a pivotal role in developing innovative low-power memory and logic devices. The efficient generation and control of skyrmions in geometrically confined systems are crucial for the development of skyrmion-based spintronic devices. In this study, we focus on investigating the non-reciprocal transport behavior of skyrmions and their interactions with boundaries of various shapes. The shape of the notch structure in the nanotrack significantly affects the dynamic behavior of magnetic skyrmions. Through micromagnetic simulation, the non-reciprocal transport properties of skyrmions in nanowires with different notch structures are investigated in this work.
基金supported by the National Natural Science Foundation of China(Grant Nos.51771127,52171188,52111530143,11974298,12374123,and 12241403)the Central Government Funds of Guiding Local Scientific and Technological Development of Sichuan Province(Grant No.2021ZYD0025)+3 种基金the Shenzhen Fundamental Research Fund(Grant No.JCYJ20210324120213037)Shenzhen Peacock Group Plan(Grant No.KQTD20180413181702403)the KeyArea Research&Development Program of Guangdong Province(Grant No.2021B0101300003)the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2022A1515110863 and 2023A1515010837)。
文摘Magnetic skyrmions are topological quasiparticles with nanoscale size and high mobility,which have potential applications in information storage and spintronic devices.The manipulation of skyrmion’s dynamics in the track is an important topic due to the skyrmion Hall effect,which can deviate the skyrmions from the preferred direction.We propose a new model based on the ferromagnetic skyrmion,where the skyrmion velocity can be well controlled by adjusting the direction of the current.Using this design,we can avoid the annihilation of the skyrmion induced by the skyrmion Hall effect,which is confirmed by our micromagnetic simulation based on Mumax^(3).In the meantime,we increase the average velocity of the skyrmion by varying the intrinsic material parameters in the track,where the simulations agree well with our analytical results based on the Thiele equation.Finally,we give a phase diagram of the output of the skyrmion in the T-type track,which provides some practical ways for design of logic gates by manipulating crystalline anisotropy through the electrical control.
