Magnetic skyrmions are promising information carriers for building future high-densityand high-speed spintronic devices. However, to achieve a current-driven high-speed skyrmion motion, the required driving current density is usually very large, which could be energy inefficient and even destroy the device due to Joule heating. Here, we propose a voltage-driven skyrmion motion approach in a skyrmion shift device made of magnetic nanowires. The highspeed skyrmion motion is realized by utilizing the voltage shift, and the average skyrmion velocity reaches up to 259 m/s under 0.45 V applied voltage. In comparison with the widely studied vertical current-driven model, the energy dissipation is three orders of magnitude lower in our voltage-driven model, for the same speed motion of skyrmions. Our approach uncovers valuable opportunities for building skyrmion racetrack memories and logic devices with both ultra-low power consumption and ultra-high processing speed, which are appealing features for future spintronic applications.Magnetic skyrmions show great potential as novel information carriers in spin memory and logic devices, because they have a number of merits including small size, low driving current density and topological stability. 1-7 Manipulations of magnetic skyrmions, including creation, motion and annihilation, have been intensively studied both theoretically 8-15 and experimentally. 16-25 Electric current is preferred to manipulate the skyrmion, 26-30 especially for skyrmion motion. [31][32][33][34][35][36][37][38] The threshold current density to drive skyrmions is around 10 6 A • m −2 , which is over 5 orders of magnitude lower than that of conventional domain walls (DWs). 26 However, a large driving current density is required to achieve high-speed skyrmion motion for fast information processing, which would result in significant amount of Joule heating, 1,36 and induce instability of devices. 3,12 In addition, for current-driven skyrmion motion, geometric patterns 39,40 or additional electric gates 41 are usually attached to pin the skyrmion for realizing the addressable control, which increase the cost of operating energy and limit the maximum speed of skyrmion motion. For these reasons, more efficient and reliable means for controlling high-speed skyrmion motion are required.Instead of current-driven approach, various approaches like spin wave, 9,19 magnetic field gradient, 14 and many more, have been proposed for driving skyrmion motion. Most of these methods lack practical convenience in integrated electrical circuit application and may not be energy efficient for commercial use.The electric field or voltage has been proposed to be an energy-efficient method to manipulate magnetism 42,43 and has been progressively applied to the development of skyrmionbased applications. 25,44,45 Very recently, a voltage controlled magnetic anisotropy (VCMA) gradient model to drive skyrmions was numerically shown by Wang et al.. 46 Wherein, a wedged insulating layer is used to generate the magnetic anisotro...
When a semicrystalline polymer melt is processed in intense flow, the nucleation rate can be accelerated and the resultant morphology is transformed to anisotropic structures. These cumulative changes to the crystallization process are referred to as flow-induced crystallization (FIC). In this study, shear flow-induced crystal formations of poly(ether ether ketone) (PEEK) are investigated after applying a short-term shear (γ̇ = 20 s–1 and t s < 230 s) via rheology and ex situ small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS). Using rheology, three types of dynamic response are monitored during FIC: no flow effect, nucleation acceleration, and instant crystal growth without crystallization induction time. Ex situ SAXS is employed with sheared PEEK disks to evaluate the flow-induced lamellar structure and orientation. The short-term shear changes the fraction and degree of lamellar stack orientation, whereas the lamellar structure is barely affected by shear, in terms of the long spacing (L* = 14.6 nm), linear crystallinity (χc = 0.34), and crystalline and amorphous layer thicknesses (Lc = 5.0 nm and La = 9.6 nm). Ex situ WAXS patterns indicate that PEEK chains (c-axis) are aligned in the shear direction within crystalline domains.
Background Drought is global environmental stress that limits crop yields. Plant-associated microbiomes play a crucial role in determining plant fitness in response to drought, yet the fundamental mechanisms for maintaining microbial community stability under drought disturbances in wild rice are poorly understood. We make explicit comparisons of leaf, stem, root and rhizosphere microbiomes from the drought-tolerant wild rice (Oryza longistaminata) in response to drought stress. Results We find that the response of the wild rice microbiome to drought was divided into aboveground–underground patterns. Drought reduced the leaf and stem microbial community diversity and networks stability, but not that of the roots and rhizospheres. Contrary to the aboveground microbial networks, the drought-negative response taxa exhibited much closer interconnections than the drought-positive response taxa and were the dominant network hubs of belowground co-occurrence networks, which may contribute to the stability of the belowground network. Notably, drought induces enrichment of Actinobacteria in belowground compartments, but not the aboveground compartment. Additionally, the rhizosphere microbiome exhibited a higher proportion of generalists and broader habitat niche breadth than the microbiome at other compartments, and drought enhanced the proportion of specialists in all compartments. Null model analysis revealed that both the aboveground and belowground-community were governed primarily by the stochastic assembly process, moreover, drought decreased ‘dispersal limitation’, and enhanced ‘drift’. Conclusions Our results provide new insight into the different strategies and assembly mechanisms of the above and belowground microbial community in response to drought, including enrichment of taxonomic groups, and highlight the important role of the stochastic assembly process in shaping microbial community under drought stress.
In this work, magnesium borate fiber (MBO) is used as a functional ceramic to coat onto a polypropylene (PP) separator (MBO@PP). This MBO coating layer increases the lithium‐ion transference number (tLi+) from 0.24 to 0.57 in the LiPF6‐based electrolyte due to the MBO acting as Lewis acid sites interacts with Lewis base PFbold6- . The increase in the tLi+ reduces the concentration polarization and promotes the migration of lithium ions. Besides, the prepared MBO@PP separator has better wettability with liquid electrolyte, the electrolyte uptake as well as thermal stability. The LiFePO4 half‐coin with MBO@PP separator not only had better cycle stability, but also had a higher capacity retention rate at high current.
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