Different than covalently bonded magnetic multilayer systems,high-quality interfaces without dangling bonds in van der Waals(vd W)junctions of two-dimensional(2D)layered magnetic materials offer opportunities to reali...Different than covalently bonded magnetic multilayer systems,high-quality interfaces without dangling bonds in van der Waals(vd W)junctions of two-dimensional(2D)layered magnetic materials offer opportunities to realize novel functionalities.Here,we report the fabrication of multi-state vertical spin valves without spacer layers by using vd W homo-junctions in which exfoliated Fe3GeTe2 nanoflakes act as ferromagnetic electrodes and/or interlayers.We demonstrate the typical behavior of two-state and threestate magnetoresistance for devices with two and three Fe3GeTe2 nanoflakes,respectively.Distinct from traditional spin valves with sandwich structures,our novel homo-junction-based spin-valve structure allows the straightforward realization of multi-state magnetic devices.Our work demonstrates the possibility of extend multi-state,non-volatile spin information to 2 D magnetic homo-junctions,and it emphasizes the utility of vd W interface as a fundamental building block for spintronic devices.展开更多
Two-dimensional van der Waals(2D vdW)magnets have attracted great attention recently and possess the unprecedented advantages of incorporating high-quality vdW heterostructures and homostructures into spintronic devic...Two-dimensional van der Waals(2D vdW)magnets have attracted great attention recently and possess the unprecedented advantages of incorporating high-quality vdW heterostructures and homostructures into spintronic devices,and exploring various physical phenomena or technologies.Among them,Fe_(5)GeTe_(2)(F5GT)has ferromagnetic order close to room temperature,however the magnetic properties near its intrinsic transitions and F5GT-based 2D devices remain mostly unexplored.Here,we systematically demonstrate the peculiar magnetic properties of Fe_(5)GeTe_(2)nanoflakes near its intrinsic transition temperature(Tp)which is far lower than its Curie temperature(TC)of~265 K,and firstly discover anomalous magnetoresistance effect in F5GT homo-junctions by magneto-transport measurements.The strongest anomalous Hall effect occurs around Tp which is located in a temperature range from 130 to 160 K for the F5GT nanoflakes with different thicknesses.Furthermore,negative magnetoresistance(N-MR)and butterfly-shaped magnetoresistance(B-MR)are observed in F5GT homo-junction devices,and they appeared only in an intermediate temperature range from 110 to 160 K,noticeably showing the maxima near the T_(p)rather than the lowest temperature.Our experimental results clearly reveal the significant influence of intrinsic transitions on magnetic properties of F5GT and magnetoresistance effect in F5GT homo-junction devices,which imply a new strategy to achieve highperformance 2D spintronic devices by tuning intrinsic magnetic or structural transitions in 2D vdW magnets.展开更多
基金supported by the National Key R&D Program of China (2017YFA0303400 and 2017YFB0405700)the National Natural Science foundation of China (61774144)+2 种基金Beijing Natural Science Foundation Key Program (Z190007)the Project from Chinese Academy of Sciences (QYZDY-SSW-JSC020, XDPB12, and XDB28000000)K C Wong Education Foundation。
文摘Different than covalently bonded magnetic multilayer systems,high-quality interfaces without dangling bonds in van der Waals(vd W)junctions of two-dimensional(2D)layered magnetic materials offer opportunities to realize novel functionalities.Here,we report the fabrication of multi-state vertical spin valves without spacer layers by using vd W homo-junctions in which exfoliated Fe3GeTe2 nanoflakes act as ferromagnetic electrodes and/or interlayers.We demonstrate the typical behavior of two-state and threestate magnetoresistance for devices with two and three Fe3GeTe2 nanoflakes,respectively.Distinct from traditional spin valves with sandwich structures,our novel homo-junction-based spin-valve structure allows the straightforward realization of multi-state magnetic devices.Our work demonstrates the possibility of extend multi-state,non-volatile spin information to 2 D magnetic homo-junctions,and it emphasizes the utility of vd W interface as a fundamental building block for spintronic devices.
基金This work was financially supported by the National Key Research and Development Program of China(No.2022YFA1204004)the National Natural Science Foundation of China(Nos.52071026,52130103,51971026,and 52201288)+3 种基金the ISF-NSFC Joint Research Program(No.51961145305)the Beijing Natural Science Foundation Key Program(No.Z190007)the open research fund of Songshan Lake Materials Laboratory(No.2022SLABFN18)the Fundamental Research Funds for the Central Universities(No.06500140).
文摘Two-dimensional van der Waals(2D vdW)magnets have attracted great attention recently and possess the unprecedented advantages of incorporating high-quality vdW heterostructures and homostructures into spintronic devices,and exploring various physical phenomena or technologies.Among them,Fe_(5)GeTe_(2)(F5GT)has ferromagnetic order close to room temperature,however the magnetic properties near its intrinsic transitions and F5GT-based 2D devices remain mostly unexplored.Here,we systematically demonstrate the peculiar magnetic properties of Fe_(5)GeTe_(2)nanoflakes near its intrinsic transition temperature(Tp)which is far lower than its Curie temperature(TC)of~265 K,and firstly discover anomalous magnetoresistance effect in F5GT homo-junctions by magneto-transport measurements.The strongest anomalous Hall effect occurs around Tp which is located in a temperature range from 130 to 160 K for the F5GT nanoflakes with different thicknesses.Furthermore,negative magnetoresistance(N-MR)and butterfly-shaped magnetoresistance(B-MR)are observed in F5GT homo-junction devices,and they appeared only in an intermediate temperature range from 110 to 160 K,noticeably showing the maxima near the T_(p)rather than the lowest temperature.Our experimental results clearly reveal the significant influence of intrinsic transitions on magnetic properties of F5GT and magnetoresistance effect in F5GT homo-junction devices,which imply a new strategy to achieve highperformance 2D spintronic devices by tuning intrinsic magnetic or structural transitions in 2D vdW magnets.
