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1.
Small ; 20(29): e2311978, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38361184

RESUMEN

Developing efficient and stable halide perovskite-based photocatalysts for highly selectivity reduction CO2 to valuable fuels remains a significant challenge due to their intrinsic instability. Herein, a novel heterostructure featuring 2D Cs3Sb2I9 nanosheets on a 3D flower-like mesoporous NiTiO3 framework using a top-down stepwise membrane fabrication technique is constructed. The unique bilayer heterostructure formed on the 3D mesoporous framework endowed NiTiO3/Cs3Sb2I9 with sufficient and close interface contact, minimizing charge transport distance, and effectively promoting the charge transfer at the interface, thus improving the reaction efficiency of the catalyst surface. As revealed by characterization and calculation, the coupling of Cs3Sb2I9 with NiTiO3 facilitates the hydrogenation process during catalytic, directing reaction intermediates toward highly selective CH4 production. Furthermore, the van der Waals forces inherent in the 3D/2D heterostructure with face-to-face contact provide superior stability, ensuring the efficient realization of photocatalytic CO2 reduction to CH4. Consequently, the optimized 3D/2D NiTiO3/Cs3Sb2I9 heterostructure demonstrates an impressive CH4 yield of 43.4 µmol g-1 h-1 with a selectivity of up to 88.6%, surpassing most reported perovskite-based photocatalysts to date. This investigation contributes to overcoming the challenges of commercializing perovskite-based photocatalysts and paves the way for the development of sustainable and efficient CO2 conversion technologies.

2.
Nano Lett ; 22(21): 8437-8444, 2022 11 09.
Artículo en Inglés | MEDLINE | ID: mdl-36260522

RESUMEN

Spintronics has been recently extended to neuromorphic computing because of its energy efficiency and scalability. However, a biorealistic spintronic neuron with probabilistic "spiking" and a spontaneous reset functionality has not been demonstrated yet. Here, we propose a biorealistic spintronic neuron device based on the heavy metal (HM)/ferromagnet (FM)/antiferromagnet (AFM) spin-orbit torque (SOT) heterostructure. The spintronic neuron can autoreset itself after firing due to the exchange bias of the AFM. The firing process is inherently stochastic because of the competition between the SOT and AFM pinning effects. We also implement a restricted Boltzmann machine (RBM) and stochastic integration multilayer perceptron (SI-MLP) using our proposed neuron. Despite the bit-width limitation, the proposed spintronic model can achieve an accuracy of 97.38% in pattern recognition, which is even higher than the baseline accuracy (96.47%). Our results offer a spintronic device solution to emulate biologically realistic spiking neurons.


Asunto(s)
Modelos Neurológicos , Neuronas , Neuronas/fisiología , Redes Neurales de la Computación , Imanes , Torque
3.
Phys Chem Chem Phys ; 22(31): 17503-17512, 2020 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-32716457

RESUMEN

It is known that rare-earth manganites LnMnO3 with Ln = La to Gd are typical Mott insulators favoring the A-type antiferromagnetic (A-AFM) state. Certainly no ferroelectricity can be possible although the alternatively stacked LnO layers are both polar. Nevertheless, under the inspiration that one plus one is more than two, it is appreciated that by combining two components of this manganite series into a superlattice functionality is added. In this work, we construct a (001)-oriented LaMnO3/RMnO3 (R = Pr, Pm, Sm and Gd) superlattice and investigate the possible emergent ferroelectricity by means of first-principles calculations. It is revealed that the lattice matching in these superlattices may generate lattice distortions to each component based on the scenario of hybrid improper ferroelectricity, resulting in spontaneous ferroelectric polarization, which is larger than the traditional type II Ln'MnO3 (Ln' radius is smaller than that of Gd) polarization. In the meantime, the A-AFM state remains the magnetic ground state of these superlattices. Furthermore, it is predicted that the externally imposed in-plane compressive strain can trigger the semiconductor to half-metal transitions accompanying the A-AFM to ferromagnetic (FM) transitions. The present work sheds light on the possibility to design multiferroic materials and functionality by tailoring artificial superlattices/heterostructures from those non-ferroelectric systems, and to design electronic devices by utilizing the electronic transport properties under epitaxial strain.

4.
PLoS One ; 19(2): e0297456, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38346062

RESUMEN

The establishment of green finance reform and innovation (GFRI) pilot zone is an important measure of the Chinese government to urge enterprises to develop green transformation. This paper explores the impact of pilot policies in the GFRI pilot zone on corporate environmental investment. Based on 819 A-share listed enterprises from 2010 to 2020, our staggered difference-in-differences (staggered DID) estimation documents revealed that enterprises in the GFRI pilot zone significantly increased the corporate environmental investment efficiency but reduced the scale of corporate environmental investment.This conclusion remained robust after Propensity Scores Matching difference-in-differences (PSM-DID), replacing dependent variables, and shortening the time window. We contend that the increased research and development (R&D) expenditure and technological innovation are the potential mechanisms at work. Heterogeneity analysis showed that the establishment of GFRI improved the environmental investment efficiency of polluting enterprises but had no effect on green enterprises.Meanwhile, the effect of GFRI exhibited heterogeneity in the type of enterprise ownership. This paper evaluates the implementation effect of GFRI from the perspective of corporate environmental investment, and provides theoretical support and an empirical basis for green finance policy to serve China's green economy.


Asunto(s)
Política Ambiental , Política Fiscal , Inversiones en Salud , Desarrollo Sostenible , Crecimiento Sostenible , China , Gobierno , Organizaciones , Desarrollo Económico , Desarrollo Sostenible/economía
5.
Diabetol Metab Syndr ; 16(1): 146, 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38956716

RESUMEN

BACKGROUND: Diabetic cardiomyopathy (DCM) stands as the primary cause of heart failure and mortality among patients with diabetes. Nevertheless, conventional treatment approaches are limited in their ability to effectively prevent myocardial tissue damage itself. Mesenchymal stem cell (MSC) therapy exhibits immense potential for treating DCM; however, the precise mechanisms involved in regulating inflammatory responses and pyroptosis processes, an emerging form of cellular death, within myocardial cells remain elusive. Hence, it is imperative to further elucidate the precise underlying mechanisms to facilitate the clinical implementation of MSC therapy. METHODS: In vivo, we established a DCM mouse model by administering streptozotocin and fed the mice a high-glucose and high-fat diet, followed by MSC therapy. Cardiac function and myocardial injury were evaluated through echocardiography and histological analysis. Furthermore, the levels of inflammation and pyroptosis were assessed using ELISA, Western blotting, and qRT-PCR. In vitro experiments involved inducing H9C2 myocardial cell damage with high glucose treatment, followed by coculture with MSCs to investigate their role in modulating inflammation and pyroptosis mechanisms. RESULTS: MSCs can maintain cardiac function and alleviate myocardial injury in mice with DCM. Moreover, they effectively suppress the activation of NLRP3 and reduce the release of inflammatory factors (such as IL-1ß and ROS), thereby further downregulating the expression of pyroptosis-related proteins including NLRP3, Caspase-1, and GSDMD. Additionally, we experimentally validated that MSCs exert their therapeutic effects by promoting the expression of miR-223-3p in cardiac myocytes; however, this effect can be reversed by an miR-223-3p inhibitor. CONCLUSION: MSCs effectively mitigate the release of inflammatory factors and cell lysis caused by pyroptosis through the regulation of the miR-223-3p/NLRP3 pathway, thereby safeguarding cardiomyocytes against damage in DCM. This mechanism establishes a novel theoretical foundation for the clinical treatment of cardiac conditions utilizing MSCs.

6.
Chem Asian J ; 19(15): e202400411, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38719729

RESUMEN

In this paper, we have established an operationally convenient protocol for the rapid construction of polysubstituted methyleneindene and quinoline derivatives under mild conditions. This new synthetic method is achieved through the conversion of acetyl-substituted methylenecyclopropanes with TsOH ⋅ H2O and ortho-amino-substituted methylenecyclopropanes with aromatic aldehyde and TsOH ⋅ H2O, respectively. A variety of transformations of the obtained products was demonstrated. The plausible reaction mechanisms were also proposed.

7.
IEEE Trans Pattern Anal Mach Intell ; 46(5): 3064-3078, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38055367

RESUMEN

Recently, brain-inspired spiking neural networks (SNNs) have demonstrated promising capabilities in solving pattern recognition tasks. However, these SNNs are grounded on homogeneous neurons that utilize a uniform neural coding for information representation. Given that each neural coding scheme possesses its own merits and drawbacks, these SNNs encounter challenges in achieving optimal performance such as accuracy, response time, efficiency, and robustness, all of which are crucial for practical applications. In this study, we argue that SNN architectures should be holistically designed to incorporate heterogeneous coding schemes. As an initial exploration in this direction, we propose a hybrid neural coding and learning framework, which encompasses a neural coding zoo with diverse neural coding schemes discovered in neuroscience. Additionally, it incorporates a flexible neural coding assignment strategy to accommodate task-specific requirements, along with novel layer-wise learning methods to effectively implement hybrid coding SNNs. We demonstrate the superiority of the proposed framework on image classification and sound localization tasks. Specifically, the proposed hybrid coding SNNs achieve comparable accuracy to state-of-the-art SNNs, while exhibiting significantly reduced inference latency and energy consumption, as well as high noise robustness. This study yields valuable insights into hybrid neural coding designs, paving the way for developing high-performance neuromorphic systems.

8.
Nat Commun ; 15(1): 1814, 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-38418454

RESUMEN

Current-induced spin torques enable the electrical control of the magnetization with low energy consumption. Conventional magnetic random access memory (MRAM) devices rely on spin-transfer torque (STT), this however limits MRAM applications because of the nanoseconds incubation delay and associated endurance issues. A potential alternative to STT is spin-orbit torque (SOT). However, for practical, high-speed SOT devices, it must satisfy three conditions simultaneously, i.e., field-free switching at short current pulses, short incubation delay, and low switching current. Here, we demonstrate field-free SOT switching at sub-ns timescales in a CoFeB/Ti/CoFeB ferromagnetic trilayer, which satisfies all three conditions. In this trilayer, the bottom magnetic layer or its interface generates spin currents with polarizations in both in-plane and out-of-plane components. The in-plane component reduces the incubation time, while the out-of-plane component realizes field-free switching at a low current. Our results offer a field-free SOT solution for energy-efficient scalable MRAM applications.

9.
IEEE Trans Image Process ; 32: 4543-4554, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37531308

RESUMEN

Composing Text and Image to Image Retrieval (CTI-IR) aims at finding the target image, which matches the query image visually along with the query text semantically. However, existing works ignore the fact that the reference text usually serves multiple functions, e.g., modification and auxiliary. To address this issue, we put forth a unified solution, namely Hierarchical Aggregation Transformer incorporated with Cross Relation Network (CRN). CRN unifies modification and relevance manner in a single framework. This configuration shows broader applicability, enabling us to model both modification and auxiliary text or their combination in triplet relationships simultaneously. Specifically, CRN includes: 1) Cross Relation Network comprehensively captures the relationships of various composed retrieval scenarios caused by two different query text types, allowing a unified retrieval model to designate adaptive combination strategies for flexible applicability; 2) Hierarchical Aggregation Transformer aggregates top-down features with Multi-layer Perceptron (MLP) to overcome the limitations of edge information loss in a window-based multi-stage Transformer. Extensive experiments demonstrate the superiority of the proposed CRN over all three fashion-domain datasets. Code is available at github.com/yan9qu/crn.

10.
Front Bioeng Biotechnol ; 11: 1073238, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36845177

RESUMEN

Quiescence is a cellular state of reversible growth arrest required to maintain homeostasis and self-renewal. Entering quiescence allows the cells to remain in the non-dividing stage for an extended period of time and enact mechanisms to protect themselves from damage. Due to the extreme nutrient-deficient microenvironment in the intervertebral disc (IVD), the therapeutic effect of cell transplantation is limited. In this study, nucleus pulposus stem cells (NPSCs) were preconditioned into quiescence through serum starvation in vitro and transplanted to repair intervertebral disc degeneration (IDD). In vitro, we investigated apoptosis and survival of quiescent NPSCs in a glucose-free medium without fetal bovine serum. Non-preconditioned proliferating NPSCs served as controls. In vivo, the cells were transplanted into a rat model of IDD induced by acupuncture, and the intervertebral disc height, histological changes, and extracellular matrix synthesis were observed. Finally, to elucidate the mechanisms underlying the quiescent state of NPSCs, the metabolic patterns of the cells were investigated through metabolomics. The results revealed that quiescent NPSCs decreased apoptosis and increased cell survival when compared to proliferating NPSCs both in vitro and in vivo, as well as maintained the disc height and histological structure significantly better than that by proliferating NPSCs. Furthermore, quiescent NPSCs have generally downregulated metabolism and reduced energy requirements in response to a switch to a nutrient-deficient environment. These findings support that quiescence preconditioning maintains the proliferation and biological function potential of NPSCs, increases cell survival under the extreme environment of IVD, and further alleviates IDD via adaptive metabolic patterns.

11.
Int Immunopharmacol ; 109: 108779, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35490666

RESUMEN

Dihydrosanguinarine (DS) is one of the main chemical constituents of Corydalis bungeana Turcz. which demonstrates anti-inflammatory, antioxidant, and antimicrobial in vitro. The present study aimed to investigate the anti-inflammatory effect and its underlying mechanism of DS in vivo. The network pharmacology method was used to predict the anti-inflammatory target of DS, and it was found that PI3K-AKT signal transduction pathway was the most obvious, and the anti-inflammatory effect of DS was more specific in liver. Herein, we used AKT inhibitor AZD 5363 to block PI3K-AKT signaling pathway, to carry out animal experiments to verify the predicted results of network pharmacology. The results showed that DS exerts protective effects on LPS-induced liver inflammation in mice, and the anti-inflammatory effect of DS was attenuated after inhibiting AKT. To elucidate the potential molecular mechanisms, we performed RNA-sequence analysis in liver tissues. Transcriptome analysis showed that the "TNF signaling pathway" and "IL-17 signaling pathway" had the highest enrichment of differentially expressed genes (DEGs). Then, TNF/IL-17/PI3K-AKT signal pathways were analyzed by GSEA. It was found that AKT3, CCL2, FOS, IL-17A, IL-17RA, IL-17RE, PI3KCA, TRAF3IP2, CREB5, ICAM-1, VCAM-1, IL-1ß, IL-6, TNF-α and CXCL1/2/3 were significantly regulated by DS. The results of RNA-seq immuneCC predictive showed that DS could inhibit the inflammatory response mainly by reducing the degree of macrophage infiltration induced by LPS. At the same time, we use RT-qPCR, IF, WB techniques to verify the core anti-inflammatory differential genes of DS at the gene and protein expression level, confirming that DS can regulate the inflammatory response by regulating the gene expression level of TNF/IL-17/PI3K-AKT signal pathway. We also used HPLC-Q-TOF/MS technology to explore the biotransformation products of DS in the blood and liver of mice under inflammatory conditions and established the docking model of DS and its transformed compound with TNF-α, IL-17A, AKT3 and IL-6, which is the key target from RNA-seq analysis in this study. The results showed that DS strongly interacted with four proteins in the form of prototypes and demethylated products and exhibited anti-inflammatory effects. Our research shows that DS exerts its anti-hepatitis effect mainly by inhibiting the excessive infiltration of macrophages in mice liver induced by LPS and down-regulating the expression of genes related to TNF/IL-17/PI3K-AKT pathway. This study provides a new perspective on the potential therapeutic application of DS and the plasticity of anti-LPS-induced liver inflammation in DS.


Asunto(s)
Antiinflamatorios , Benzofenantridinas , Inflamación , Isoquinolinas , Animales , Antiinflamatorios/farmacología , Benzofenantridinas/farmacología , Citocinas/metabolismo , Inflamación/inducido químicamente , Inflamación/tratamiento farmacológico , Interleucina-17/genética , Interleucina-6/genética , Isoquinolinas/farmacología , Lipopolisacáridos , Hígado/metabolismo , Ratones , Farmacología en Red , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , RNA-Seq , Factor de Necrosis Tumoral alfa/genética
12.
Tissue Eng Regen Med ; 19(5): 961-968, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35809187

RESUMEN

Senescence is an inevitable natural life process that involves structural and functional degeneration of tissues and organs. Recently, the process of skin aging has attracted much attention. Determining a means to delay or even reverse skin aging has become a research hotspot in medical cosmetology and anti-aging. Dysfunction in the epidermis and fibroblasts and changes in the composition and content of the extracellular matrix are common pathophysiological manifestations of skin aging. Reactive oxygen species and matrix metalloproteinases play essential roles in this process. Stem cells are pluripotent cells that possess self-replication abilities and can differentiate into multiple functional cells under certain conditions. These cells also possess a strong ability to facilitate tissue repair and regeneration. Stem cell transplantation has the potential for application in anti-aging therapy. Increasing studies have demonstrated that stem cells perform functions through paracrine processes, particularly those involving exosomes. Exosomes are nano-vesicular substances secreted by stem cells that participate in cell-to-cell communication by transporting their contents into target cells. In this chapter, the biological characteristics of exosomes were reviewed, including their effects on extracellular matrix formation, epidermal cell function, fibroblast function and antioxidation. Exosomes derived from stem cells may provide a new means to reverse skin aging.


Asunto(s)
Exosomas , Envejecimiento de la Piel , Fibroblastos , Especies Reactivas de Oxígeno , Células Madre
13.
Oncol Rep ; 46(3)2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34278510

RESUMEN

Following the publication of this paper, it was drawn to the Editors' attention by a concerned reader that certain of the western blotting data shown in Figs. 3A and 4A, and tumor images in Fig. 5A, bore unexpected similarities to data appearing in different form in other articles by different authors. Owing to the fact that some of the contentious data in the above article had already been published elsewhere, or were already under consideration for publication, prior to its submission to Oncology Reports, the Editor has decided that this paper should be retracted from the Journal. After having been in contact with the authors, they agreed with the decision to retract the paper. The Editor apologizes to the readership for any inconvenience caused. [the original article was published in Oncology Reports 33: 2537­2544, 2015; DOI: 10.3892/or.2015.3832].

14.
Zool Res ; 41(4): 381-394, 2020 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-32400977

RESUMEN

Magnetic brain stimulation has greatly contributed to the advancement of neuroscience. However, challenges remain in the power of penetration and precision of magnetic stimulation, especially in small animals. Here, a novel combined magnetic stimulation system (c-MSS) was established for brain stimulation in mice. The c-MSS uses a mild magnetic pulse sequence and injection of superparamagnetic iron oxide (SPIO) nanodrugs to elevate local cortical susceptibility. After imaging of the SPIO nanoparticles in the left prelimbic (PrL) cortex in mice, we determined their safety and physical characteristics. Depressive-like behavior was established in mice using a chronic unpredictable mild stress (CUMS) model. SPIO nanodrugs were then delivered precisely to the left PrL cortex using in situ injection. A 0.1 T magnetic field (adjustable frequency) was used for magnetic stimulation (5 min/session, two sessions daily). Biomarkers representing therapeutic effects were measured before and after c-MSS intervention. Results showed that c-MSS rapidly improved depressive-like symptoms in CUMS mice after stimulation with a 10 Hz field for 5 d, combined with increased brain-derived neurotrophic factor (BDNF) and inactivation of hypothalamic-pituitary-adrenal (HPA) axis function, which enhanced neuronal activity due to SPIO nanoparticle-mediated effects. The c-MSS was safe and effective, representing a novel approach in the selective stimulation of arbitrary cortical targets in small animals, playing a bioelectric role in neural circuit regulation, including antidepressant effects in CUMS mice. This expands the potential applications of magnetic stimulation and progresses brain research towards clinical application.


Asunto(s)
Depresión/terapia , Giro del Cíngulo/fisiología , Nanopartículas Magnéticas de Óxido de Hierro/administración & dosificación , Animales , Fenómenos Magnéticos , Masculino , Ratones , Ratones Endogámicos C57BL
15.
Huan Jing Ke Xue ; 40(2): 876-884, 2019 Feb 08.
Artículo en Zh | MEDLINE | ID: mdl-30628356

RESUMEN

Wetlands are important sources and sinks for N2O. Exploring the role of N2O emissions in saline-alkali wetlands has great significance in understanding the nitrification mechanism of N2O production and assessing the role of saline-alkali wetlands in the greenhouse effect. The present study examined the N2O fluxes and environmental factors of a typical Zhalong reed wetland during the growing season. The results suggested that the N2O fluxes tended to decrease in volatility, with the highest value in mid-July. The mean flux of N2O was (37.49±15.75) µg·(m2·h)-1, indicating that the typical Zhalong reed wetland was a source of N2O. The N2O fluxes exhibited a significantly positive correlation with soil temperature at different depths (P<0.05), and the impact of the upper soil temperature on N2O flux was higher than that of deep soil. In the flooding period, the relationship between N2O fluxes and water table depth was negatively correlated (P<0.05). Meanwhile, the TOC and TN contents were lower, and the N2O flux was significantly positively correlated with the NH4+-N content in the 0-40 cm soil layer (P<0.05), but it was not related to NO3--N content. Nitrification was stronger than denitrification. There was a significant positive correlation between ammonia-oxidizing bacterial activity and soil temperature in 0-20 cm layer (P<0.01). Additionally, the activity of ammonia-oxidizing bacteria also presented significantly positive linear correlation with the N2O fluxes (P<0.001), which indicated that the release of N2O in saline-alkali wetlands was greatly affected by nitrification.

16.
Adv Mater ; 30(39): e1803612, 2018 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-30133018

RESUMEN

E-field control of antiferromagnetic (AFM) orders is promising for the realization of fast, compact, and energy-efficient AFM applications. However, as the AFM spins are strongly pinned, the E-field control process is mainly based on the exchange bias regulation that usually confines at a low temperature. Here, a new magnetoelectric (ME) coupling mechanism for the modulation of AFM orders at room temperature is explored. Based on the FeCoB/Ru/FeCoB/(011) Pb(Mg1/3 Nb2/3 )O3 -PbTiO3 (PMN-PT) synthetic antiferromagnetic (SAF) heterostructures, the external E-field generates relative magnetization switching in the two ferromagnetic (FM) layers, leading the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction tuning. This voltage-induced switching behavior can be repeated in a stable and reversible manner for various SAFs, which is a key challenge in the E-field control of AFM coupling and is not resolved yet. The voltage-induced RKKY interaction changes by analyzing the dynamic optical and acoustic modes is quantified, and with first-principles calculations, it is found that the distortion of the Fermi surface by the lattice reconstruction is the key of the relative magnetization switching and RKKY interaction modulation. This voltage control of the RKKY interaction in ME heterostructures provides an easy way to achieve the next generation of AFM/FM spintronic applications.

17.
Adv Mater ; 30(22): e1800449, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29663532

RESUMEN

To meet the demand of developing compatible and energy-efficient flexible spintronics, voltage manipulation of magnetism on soft substrates is in demand. Here, a voltage tunable flexible field-effect transistor structure by ionic gel (IG) gating in perpendicular synthetic anti-ferromagnetic nanostructure is demonstrated. As a result, the interlayer Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction can be tuned electrically at room temperature. With a circuit gating voltage, anti-ferromagnetic (AFM) ordering is enhanced or converted into an AFM-ferromagnetic (FM) intermediate state, accompanying with the dynamic domain switching. This IG gating process can be repeated stably at different curvatures, confirming an excellent mechanical property. The IG-induced modification of interlayer exchange coupling is related to the change of Fermi level aroused by the disturbance of itinerant electrons. The voltage modulation of RKKY interaction with excellent flexibility proposes an application potential for wearable spintronic devices with energy efficiency and ultralow operation voltage.

18.
ACS Appl Mater Interfaces ; 10(35): 29750-29756, 2018 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-30094986

RESUMEN

In spite of recent rapid development of flexible electronics, voltage-tunable spintronic structures and devices on flexible substrates have been rarely studied. Here, voltage control of magnetic anisotropy (VCMA) is demonstrated via ionic gel (IG) gating on flexible polyimide substrates with a circuit operating voltage of 1.8 V. A reversible, nonvolatile VCMA switching of 114 Oe is achieved in Pt/Fe/Pt multilayer, where the spatial magnetic anisotropy distribution is determined quantitatively by electron spin resonance technique. This IG gating process is repeatable as the substrates are under different bending conditions. The voltage modulation of magnetic anisotropy through IG gating with excellent flexibility proposes potential applications in low-power wearable spintronic devices.

19.
Nat Commun ; 9(1): 991, 2018 03 07.
Artículo en Inglés | MEDLINE | ID: mdl-29515180

RESUMEN

To overcome the fundamental challenge of the weak natural response of antiferromagnetic materials under a magnetic field, voltage manipulation of antiferromagnetic interaction is developed to realize ultrafast, high-density, and power efficient antiferromagnetic spintronics. Here, we report a low voltage modulation of Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction via ionic liquid gating in synthetic antiferromagnetic multilayers of FeCoB/Ru/FeCoB and (Pt/Co)2/Ru/(Co/Pt)2. At room temperature, the distinct voltage control of transition between antiferromagnetic and ferromagnetic ordering is realized and up to 80% of perpendicular magnetic moments manage to switch with a small-applied voltage bias of 2.5 V. We related this ionic liquid gating-induced RKKY interaction modification to the disturbance of itinerant electrons inside synthetic antiferromagnetic heterostructure and the corresponding change of its Fermi level. Voltage tuning of RKKY interaction may enable the next generation of switchable spintronics between antiferromagnetic and ferromagnetic modes with both fundamental and practical perspectives.

20.
Adv Mater ; 29(17)2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28256772

RESUMEN

Ionic-liquid gating on a functional thin film with a low voltage has drawn a lot of attention due to rich chemical, electronic, and magnetic phenomena at the interface. Here, a key challenge in quantitative determination of voltage-controlled magnetic anisotropy (VCMA) in Au/[DEME]+ [TFSI]- /Co field-effect transistor heterostructures is addressed. The magnetic anisotropy change as response to the gating voltage is precisely detected by in situ electron spin resonance measurements. A reversible change of magnetic anisotropy up to 219 Oe is achieved with a low gating voltage of 1.5 V at room temperature, corresponding to a record high VCMA coefficient of ≈146 Oe V-1 . Two gating effects, the electrostatic doping and electrochemical reaction, are distinguished at various gating voltage regions, as confirmed by X-ray photoelectron spectroscopy and atomic force microscopy experiments. This work shows a unique ionic-liquid-gating system for strong interfacial magnetoelectric coupling with many practical advantages, paving the way toward ion-liquid-gating spintronic/electronic devices.

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