Since the discovery of ferromagnetic two-dimensional (2D) van der Waals (vdW) crystals, significant interest on such 2D magnets has emerged, inspired by their appealing physical properties and integration with other 2D family for unique heterostructures. In known 2D magnets, spin-orbit coupling (SOC) stabilizes perpendicular magnetic anisotropy down to one or a few monolayers. Such a strong SOC could also lift the chiral degeneracy, leading to the formation of topological magnetic textures such as skyrmions through the Dzyaloshinskii-Moriya interaction (DMI). Here, we report the experimental observation of Néel-type chiral magnetic skyrmions and their lattice (SkX) formation in a vdW ferromagnet Fe 3 GeTe 2 (FGT). We demonstrate the ability to drive an individual skyrmion by short current pulses along a vdW heterostructure, FGT/h-BN, as highly required for any skyrmion-based spintronic device. Using first principle calculations supported by experiments, we unveil the origin of DMI being the interfaces with oxides, which then allows us to engineer vdW heterostructures for desired chiral states. Our finding opens the door to topological spin textures in the 2D vdW magnet and their potential device application.
Creatively
constructing Z-scheme composites is a promising and
common strategy for designing effective photocatalyst systems. Herein,
we synthesized Z-scheme Fe2O3@Ag–ZnO@C
heterostructures from the Fe-MOFs and applied it to photodegradation
of tetracycline and methylene blue pollutants in wastewater. The optimized
sample exhibits a remarkable performance as well as stability under
visible light irradiation. The calculating and experimental results
demonstrate that the Fe2O3@ZnO nanointerface
and carbon sheath together boost the transfer efficiency of photogenerated
carriers and absorption ability, thereby improving the photocatalytic
activity. Furthermore, detailed mechanism investigation reveals the
pivotal role of reactive oxygen species (•OH and •O2
–) generated, resulting
in remarkable performance. In addition, cell biology experiments reveal
that the wastewater after photocatalytic treatment has good biological
compatibility, which is important for applications. This work provides
valuable information for constructing high-performance Z-scheme photocatalysts
from MOFs for environmental treatment.
As an effective antiviral agent, the clinical application of oseltamivir (OTV) is limited by the appearance of drug-resistant viruses. Due to their low toxicity and excellent activity, the antiviral capabilities of selenium nanoparticles (SeNPs) has attracted increasing attention in recent years. To overcome the limitation of drug resistance, the use of modified NPs with biologics to explore novel anti-influenza drugs is developing rapidly. In this study, OTV surface-modified SeNPs with superior antiviral properties and restriction on drug resistance were synthesized. OTV decoration of SeNPs (Se@OTV) obviously inhibited H1N1 infection and had less toxicity. Se@OTV interfered with the H1N1 influenza virus to host cells through inhibiting the activity of hemagglutinin and neuraminidase. The mechanism was that Se@OTV was able to prevent H1N1 from infecting MDCK cells and block chromatin condensation and DNA fragmentation. Furthermore, Se@OTV inhibited the generation of reactive oxygen species and activation of p53 phosphorylation and Akt. These results demonstrate that Se@OTV is a promising efficient antiviral pharmaceutical for H1N1.
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