Magnetic skyrmions in multilayer structures are considered as a new direction for the next generation of storage due to their small size,strong anti-interference ability,high current-driven mobility,and compatibility ...Magnetic skyrmions in multilayer structures are considered as a new direction for the next generation of storage due to their small size,strong anti-interference ability,high current-driven mobility,and compatibility with existing spintronic technology.In this work,we present a tunable room temperature skyrmion platform based on multilayer stacks of MgO/FeNiB/Mo.We systematically studied the creation of magnetic skyrmions in MgO/FeNiB/Mo multilayer structures with perpendicular magnetic anisotropy(PMA).In these structures,the magnetic anisotropy changes from PMA to in-plane magnetic anisotropy(IMA)as the thickness of FeNiB layer increases.By adjusting the applied magnetic field and electric current,stable and high-density skyrmions can be obtained in the material system.The discovery of this material broadens the exploration of new materials for skyrmion and promotes the development of spintronic devices based on skyrmions.展开更多
With the widespread application of legged robot in various fields,the demand for a robot with high locomotion and manipulation ability is increasing.Adding an extra arm is a useful but general method for a legged robo...With the widespread application of legged robot in various fields,the demand for a robot with high locomotion and manipulation ability is increasing.Adding an extra arm is a useful but general method for a legged robot to obtain manipulation ability.Hence,this paper proposes a novel hexapod robot with two integrated leg–arm limbs that obtain dexterous manipulation functions besides locomotion ability without adding an extra arm.The manipulation modes can be divided into coordinated manipulation condition and single-limb manipulation condition.The former condition mainly includes fixed coordinated clamping case and fixed coordinated shearing case.For the fixed coordinated clamping case,the degrees of freedom(DOFs)analysis of equivalent parallel mechanism by using screw theory and the constraint equation of two integrated limbs are established.For the fixed coordinated shearing case,the coordinated working space is determined,and an ideal coordinated manipulation ball is presented to guide the coordinated shearing task.In addition,the constraint analysis of two adjacent integrated limbs is performed.Then,mobile manipulation with one integrated leg–arm limb while using pentapod gait is discussed as the single-limb manipulation condition,including gait switching analysis between hexapod gait and pentapod gait,different pentapod gaits analysis,and a complex six-DOF manipulation while walking.Corresponding experiments are implemented,including clamping tasks with two integrated limbs,coordinated shearing task by using two integrated limbs,and mobile manipulation with pentapod gait.This robot provides a new approach to building a multifunctional locomotion platform.展开更多
针对无源电磁调控中目标模拟逼真度不高的问题,基于有源频率选择表面(Active Frequency Selective Surface,AFSS)的周期性间歇调制,提出了一种AFSS协同调控的雷达目标模拟方法。根据雷达信号参数和AFSS周期性间歇调制信号参数确定目标...针对无源电磁调控中目标模拟逼真度不高的问题,基于有源频率选择表面(Active Frequency Selective Surface,AFSS)的周期性间歇调制,提出了一种AFSS协同调控的雷达目标模拟方法。根据雷达信号参数和AFSS周期性间歇调制信号参数确定目标的距离分布,再使AFSS调制信号的相位满足协同调控条件,即可在距离向上生成逼真度较高的模拟目标。文中给出了AFSS周期性间歇调制的基本原理,并理论推导了AFSS协同调控的实现条件。最后进行了仿真验证,仿真结果验证了该方法的可行性和有效性。展开更多
High performance of the generation,stabilization and manipulation of magnetic skyrmions prompts the application of topological multilayers in spintronic devices.Skyrmions in synthetic antiferromagnets(SAF)have been co...High performance of the generation,stabilization and manipulation of magnetic skyrmions prompts the application of topological multilayers in spintronic devices.Skyrmions in synthetic antiferromagnets(SAF)have been considered as a promising alternative to overcome the limitations of ferromagnetic skyrmions,such as the skyrmion Hall effect and stray magnetic field.Here,by using the Lorentz transmission electron microscopy,the interconversion between the single domain,labyrinth domain and skyrmion state can be observed by the combined manipulation of electric current and magnetic field in a Hall balance(a SAF with the core structure of[Co/Pt]_(4)/NiO/[Co/Pt]_(4)showing perpendicular magnetic anisotropy).Furthermore,high-density room temperature skyrmions can be stabilized at zero field while the external stimulus is removed and the skyrmion density is tunable.The generation and manipulation method of skyrmions in Hall balance in this study opens up a promising way to engineer SAF-skyrmion-based memory devices.展开更多
基金Project supported by the National Basic Research Program of China (Grant No.2015CB921403)the National Key Research and Development Program of China (Grant No.2016YFA0300804)+2 种基金the National Natural Science Foundation of China (Grant Nos.51871236,11874408,51431009,92263202,and 51971240)the Science Center of the National Science Foundation of China (Grant No.52088101)the Strategic Priority Research Program (B,Grant No.XDB33030200)of the Chinese Academy of Sciences (CAS)。
文摘Magnetic skyrmions in multilayer structures are considered as a new direction for the next generation of storage due to their small size,strong anti-interference ability,high current-driven mobility,and compatibility with existing spintronic technology.In this work,we present a tunable room temperature skyrmion platform based on multilayer stacks of MgO/FeNiB/Mo.We systematically studied the creation of magnetic skyrmions in MgO/FeNiB/Mo multilayer structures with perpendicular magnetic anisotropy(PMA).In these structures,the magnetic anisotropy changes from PMA to in-plane magnetic anisotropy(IMA)as the thickness of FeNiB layer increases.By adjusting the applied magnetic field and electric current,stable and high-density skyrmions can be obtained in the material system.The discovery of this material broadens the exploration of new materials for skyrmion and promotes the development of spintronic devices based on skyrmions.
基金This paper was funded by the National Key R&D Program of China(Grant No.2019YFB1309600)the National Natural Science Foundation of China(Grant Nos.51775011 and 91748201).
文摘With the widespread application of legged robot in various fields,the demand for a robot with high locomotion and manipulation ability is increasing.Adding an extra arm is a useful but general method for a legged robot to obtain manipulation ability.Hence,this paper proposes a novel hexapod robot with two integrated leg–arm limbs that obtain dexterous manipulation functions besides locomotion ability without adding an extra arm.The manipulation modes can be divided into coordinated manipulation condition and single-limb manipulation condition.The former condition mainly includes fixed coordinated clamping case and fixed coordinated shearing case.For the fixed coordinated clamping case,the degrees of freedom(DOFs)analysis of equivalent parallel mechanism by using screw theory and the constraint equation of two integrated limbs are established.For the fixed coordinated shearing case,the coordinated working space is determined,and an ideal coordinated manipulation ball is presented to guide the coordinated shearing task.In addition,the constraint analysis of two adjacent integrated limbs is performed.Then,mobile manipulation with one integrated leg–arm limb while using pentapod gait is discussed as the single-limb manipulation condition,including gait switching analysis between hexapod gait and pentapod gait,different pentapod gaits analysis,and a complex six-DOF manipulation while walking.Corresponding experiments are implemented,including clamping tasks with two integrated limbs,coordinated shearing task by using two integrated limbs,and mobile manipulation with pentapod gait.This robot provides a new approach to building a multifunctional locomotion platform.
文摘针对无源电磁调控中目标模拟逼真度不高的问题,基于有源频率选择表面(Active Frequency Selective Surface,AFSS)的周期性间歇调制,提出了一种AFSS协同调控的雷达目标模拟方法。根据雷达信号参数和AFSS周期性间歇调制信号参数确定目标的距离分布,再使AFSS调制信号的相位满足协同调控条件,即可在距离向上生成逼真度较高的模拟目标。文中给出了AFSS周期性间歇调制的基本原理,并理论推导了AFSS协同调控的实现条件。最后进行了仿真验证,仿真结果验证了该方法的可行性和有效性。
基金supported by the Science Center of the National Science Foundation of China(Grant No.52088101)the National Natural Science Foundation of China(Grant Nos.11874408,52130103,51901025,and 11904025)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB33030100)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.CAS Y201903)。
文摘High performance of the generation,stabilization and manipulation of magnetic skyrmions prompts the application of topological multilayers in spintronic devices.Skyrmions in synthetic antiferromagnets(SAF)have been considered as a promising alternative to overcome the limitations of ferromagnetic skyrmions,such as the skyrmion Hall effect and stray magnetic field.Here,by using the Lorentz transmission electron microscopy,the interconversion between the single domain,labyrinth domain and skyrmion state can be observed by the combined manipulation of electric current and magnetic field in a Hall balance(a SAF with the core structure of[Co/Pt]_(4)/NiO/[Co/Pt]_(4)showing perpendicular magnetic anisotropy).Furthermore,high-density room temperature skyrmions can be stabilized at zero field while the external stimulus is removed and the skyrmion density is tunable.The generation and manipulation method of skyrmions in Hall balance in this study opens up a promising way to engineer SAF-skyrmion-based memory devices.
