Light-Programmed Bistate Colloidal Actuation Based on Photothermal Active Plasmonic Substrate

Active particles have been regarded as the key models to mimic and understand the complex systems of nature.Although chemical and field-powered active particles have received wide attentions,lightprogrammed actuation with long-range interaction and high throughput remains elusive.Here,we utilize photothermal active plasmonic substrate made of porous anodic aluminum oxide filled with Au nanoparticles and poly(N-isopropylacrylamide)(PNIPAM)to optically oscillate silica beads with robust reversibility.The thermal gradient generated by the laser beam incurs the phase change of PNIPAM,producing gradient of surface forces and large volume changes within the complex system.The dynamic evolution of phase change and water diffusion in PNIPAM films result in bistate locomotion of silica beads,which can be programmed by modulating the laser beam.This light-programmed bistate colloidal actuation provides promising opportunity to control and mimic the natural complex systems.

Magnetic logic inverter from crossed structures of defect-free graphene with large unsaturated room temperature negative magnetoresistance

Introducing defects into graphene has been widely utilized to realize the negative magnetoresistanee(MR)effect in graphene.However,the reported graphene negative MR exhibits only^10%under 10 T at room temperature to date,which extremely limits the resolution of future spintronics devices.Moreover,intentional defect introduction can also cause unintentional degradation in graphene's intrinsic properties.In this paper,we report a magnetic logic inverter based on a crossed structure of defect-free graphene,resulting in a substantial gain of 4.81 mV/T while exhibiting room temperature operation.This crossed structure of graphene shows large unsaturated room temperature negative MR with an enhancement of up to 1,000%at 9 T.A transition behavior between negative and positive MR is observed in this crossed structure and the transition temperature can be tuned by a ratio of the conductivity between in-plane and out-of-plane transport.Our results open an intriguing path for future two-dimensional spintronics device applications.

Planar-symmetry-breaking induced antisymmetric magnetoresistance in van der Waals ferromagnet Fe_(3)GeTe_(2)

Recently discovered magnetic van der Waals(vdW)materials provide an ideal platform to explore low-dimensional magnetism and spin transport.Its vdW interaction nature opens up unprecedented opportunities to build vertically stacked heterostructures with novel properties and functionalities.By engineering the planar structure as an alternative degree of freedom,herein we demonstrate an antisymmetric magnetoresistance(MR)in a vdW Fe_(3)GeTe_(2)flake with a step terrace that breaks the planar symmetry.This antisymmetric MR originates from a sign change of the anomalous Hall effect and the continuity of the current transport near the boundary of magnetic domains at the step edge.A repeatable domain wall due to the unsynchronized magnetization switching is responsible for this sign change.Such interpretation is supported by the observation of field-dependent domain switching,and the step thickness,temperature,and magnetic field orientation dependent MR.This work opens up new opportunities to encode magnetic information by controlling the planar domain structures in vdW magnets.