Mixed-valance manganites with strong electron correlation exhibit strong potential for spintronics,where emergent magnetic behaviors,such as propagation of high-frequency spin waves and giant topological Hall Effects ...Mixed-valance manganites with strong electron correlation exhibit strong potential for spintronics,where emergent magnetic behaviors,such as propagation of high-frequency spin waves and giant topological Hall Effects can be driven by their mesoscale spin textures.Here,we create magnetic vortex clusters with flux closure spin configurations in single-crystal La0.67Sr0.33MnO3 wire.A distinctive transformation from out-of-plane domains to a vortex state is directly visualized using magnetic force microscopy at 4 K in wires when the width is below 1.0μm.The phase-field modeling indicates that the inhomogeneous strain,accompanying with shape anisotropy,plays a key role for stabilizing the flux-closure spin structure.This work offers a new perspective for understanding and manipulating the non-trivial spin textures in strongly correlated systems.展开更多
We study systematically the negative magnetoresistance(MR)effect in WTe_(2±α)flakes with different thicknesses and doping concentrations.The negative MR is sensitive to the relative orientation between electrica...We study systematically the negative magnetoresistance(MR)effect in WTe_(2±α)flakes with different thicknesses and doping concentrations.The negative MR is sensitive to the relative orientation between electrical-/magnetic-field and crystallographic orientation of WTe_(2±α).The analysis proves that the negative MR originates from chiral anomaly and is anisotropic.Maximum entropy mobility spectrum is used to analyze the electron and hole concentrations in the flake samples.It is found that the negative MR observed in WTe_(2±α)flakes with low doping concentration is small,and the high doping concentration is large.The doping-induced disorder obviously inhibits the positive MR,so the negative MR can be more easily observed.In a word,we introduce disorder to suppress positive MR by doping,and successfully obtain the negative MR in WTe_(2±α)flakes with different thicknesses and doping concentrations,which indicates that the chiral anomaly effect in WTe_(2)is robust.展开更多
基金supported by the National Key Research and Development Program of China(2016YFA0302300)the Beijing Natural Science Foundation(Z190008)+9 种基金the National Natural Science Foundation of China(11974052 and 11474024)the Beamline 1W1A of the Beijing Synchrotron Radiation Facilitythe National Natural Science Foundation of China(11604011)Beijing Institute of Technology Research Fund Program for Young Scholarsthe National Natural Science Foundation of China(11672264 and 11621062)support by the German Research Foundation DFG SFB TRR173 Spin+X,project KL1811/18the Graduate School of Excellence Materials Science in Mainz(GSC266)Peking University was supported by the National Key R&D Program of China(2016YFA0300804)the National Natural Science Foundation of China(11974023 and 51672007)the Key R&D Program of Guangdong Province(2018B030327001 and 2018B010109009).
文摘Mixed-valance manganites with strong electron correlation exhibit strong potential for spintronics,where emergent magnetic behaviors,such as propagation of high-frequency spin waves and giant topological Hall Effects can be driven by their mesoscale spin textures.Here,we create magnetic vortex clusters with flux closure spin configurations in single-crystal La0.67Sr0.33MnO3 wire.A distinctive transformation from out-of-plane domains to a vortex state is directly visualized using magnetic force microscopy at 4 K in wires when the width is below 1.0μm.The phase-field modeling indicates that the inhomogeneous strain,accompanying with shape anisotropy,plays a key role for stabilizing the flux-closure spin structure.This work offers a new perspective for understanding and manipulating the non-trivial spin textures in strongly correlated systems.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.92065110,11674031,11974048,12074334)the National Basic Research Program of China(Grant Nos.2014CB920903 and 2013CB921701)。
文摘We study systematically the negative magnetoresistance(MR)effect in WTe_(2±α)flakes with different thicknesses and doping concentrations.The negative MR is sensitive to the relative orientation between electrical-/magnetic-field and crystallographic orientation of WTe_(2±α).The analysis proves that the negative MR originates from chiral anomaly and is anisotropic.Maximum entropy mobility spectrum is used to analyze the electron and hole concentrations in the flake samples.It is found that the negative MR observed in WTe_(2±α)flakes with low doping concentration is small,and the high doping concentration is large.The doping-induced disorder obviously inhibits the positive MR,so the negative MR can be more easily observed.In a word,we introduce disorder to suppress positive MR by doping,and successfully obtain the negative MR in WTe_(2±α)flakes with different thicknesses and doping concentrations,which indicates that the chiral anomaly effect in WTe_(2)is robust.
