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When subordinates experience abusive supervision, they often respond with “fight” (e.g., organizationally-directed counterproductive work behavior: CWB-O) or “flight” reactions (e.g., turnover intentions). Drawing on cognitive appraisal theory, we propose that negative (NA) and positive affect (PA) explain these distinct responses and that coworker emotional support differentially moderates the relationships of affective states with CWB-O and turnover intention. That is, we expect that emotional support exacerbates the mediating effect of NA, whereas it weakens the mediating effect of PA. We tested the hypothesized model in two time-lagged studies, one among subordinates ( N = 162), and the other among supervisor-subordinate dyads ( N = 255 dyads). Results confirmed that the relation between abusive supervision and CWB-O was mediated by NA, and that the relation between abusive supervision and turnover intentions was mediated by PA. Coworker emotional support strengthened the mediating effect of NA, but it did not attenuate the mediating effect of PA. These results only hold for CWB-O, not for supervisor-rated CWB-O. Explanations, implications as well as limitations and ideas for future research are discussed.

Skyrmions and bimerons are versatile topological spin textures that can be used as information bits for both classical and quantum computing. The transformation between isolated skyrmions and bimerons is an essential operation for computing architecture based on multiple different topological bits. Here we report the creation of isolated skyrmions and their subsequent transformation to bimerons by harnessing the electric current-induced Oersted field and temperature-induced perpendicular magnetic anisotropy variation. The transformation between skyrmions and bimerons is reversible, which is controlled by the current amplitude and scanning direction. Both skyrmions and bimerons can be created in the same system through the skyrmion-bimeron transformation and magnetization switching. Deformed skyrmion bubbles and chiral labyrinth domains are found as nontrivial intermediate transition states. Our results may provide a unique way for building advanced information-processing devices using different types of topological spin textures in the same system., 23 pages, 5 figures

The skyrmion-substrate interaction is an important issue to consider when studying particle-like skyrmions in nanostructures, which may strongly affect the skyrmion dynamics and lead to complex dynamic phenomena. Here, we report the current-driven dynamic behaviors of particle-like skyrmions interacting with the funnel obstacle in a ferromagnetic layer. We computationally demonstrate that a funnel obstacle with enhanced perpendicular magnetic anisotropy can be used to modify the dynamics of skyrmions due to the repulsive skyrmion-funnel interaction, which could generate several nontrivial effects, including the compression, clogging, annihilation, guided motion, and capturing of skyrmions. It is also found that the funnel obstacle can separate an incoming flow of skyrmions into two asymmetric flows. Moreover, we show that it is possible to capture skyrmions by the funnel obstacle in both static and dynamic ways. Our results are useful for understanding the skyrmion dynamics interacting with the substrate and could provide guidelines for the control of skyrmion flows in a transmission channel., 15 pages, 12 figures

Magnetic skyrmions are versatile topological excitations that can be used as nonvolatile information carriers. The confinement of skyrmions in channels is fundamental for any application based on the accumulation and transport of skyrmions. Here, we report a method that allows effective position control of skyrmions in designed channels by engineered energy barriers and wells, which is realized in a magnetic multilayer film by harnessing the boundaries of patterns with modified magnetic properties. We experimentally and computationally demonstrate that skyrmions can be attracted or repelled by the boundaries of areas with modified perpendicular magnetic anisotropy and Dzyaloshinskii-Moriya interaction. By fabricating square and stripe patterns with modified magnetic properties, we show the possibility of building reliable channels for confinement, accumulation, and transport of skyrmions, which effectively protect skyrmions from being destroyed at the device edges. Our results are useful for the design of spintronic applications using either static or dynamic skyrmions.

Manipulation of three-dimensional (3D) topological objects is of both fundamental interest and practical importance in many branches of physics. Here, we show by spin dynamics simulations that the bifurcation of a 3D skyrmion string in a layered frustrated system could be induced by the dampinglike spin-orbit torque. The bifurcation of a skyrmion string happens when the skyrmion string carries a minimal topological charge of $Q=2$. We demonstrate that three types of bifurcations could be realized by applying different current injection geometries, which lead to the transformation from I-shaped skyrmion strings to Y-, X-, and O-shaped ones. Besides, different branches of a bifurcated skyrmion string may merge into an isolated skyrmion string spontaneously. The mechanism of bifurcation should be universal to any skyrmion strings with $Q\geq 2$ in the layered frustrated system and could offer a general approach to manipulate 3D stringlike topological objects for spintronic functions., Comment: 6 pages, 3 figures

Three-dimensional (3D) magnetic textures attract great attention from researchers due to their fascinating structures and dynamic behaviors. Magnetic hopfion is a prominent example of 3D magnetic textures. Here, we numerically study the mutual conversion between a Neel-type hopfion and a Neel-type toron under an external magnetic field. We also investigate the excitation modes of hopfions and torons in a film with strong perpendicular magnetic anisotropy. It is found that the Neel-type hopfion could be a stable state in the absence of the external magnetic field, and its diameter varies with the out-of-plane magnetic field. The Neel-type hopfion may transform to a Neel-type toron at an out-of-plane magnetic field of about 20 mT, where the cross section structure is a Neel-type skyrmion. The hopfion and toron show different excitation modes in the presence of an in-plane microwave magnetic field. Our results provide a method to realize the conversion between a Neel-type hopfion and a Neel-type toron, which also gives a way to distinguish Bloch-type and Neel-type hopfions., Originally submitted to PRB on 23 December 2021

The competition between external drives and interparticle interactions are important for the static and dynamic properties of topological quasiparticles in confined geometries. Here, we study the dynamics of particlelike skyrmions under a current-induced compression, where skyrmions are stabilized in a confined space and form a skyrmion solid. We find that a lattice structural transition of nanoscale skyrmions could be induced by the compression, which depends on the initial lattice configuration and the compression level. The compression effect in the skyrmion solid with strong skyrmion-skyrmion repulsion could produce a wave front showing an abrupt change of the skyrmion density, which may propagate through the skyrmion solid depending on the compression level. Besides, a chain of skyrmions on the surface of the compressed skyrmion solid could show a fast and stable motion along the surface as long as it remains within the driving region. Some skyrmions may collapse during the compression due to the destructive skyrmion-skyrmion collision, which mainly happens in the area around the skyrmion injection boundary between the driving and compressive regions. Our results are useful for understanding the compression physics of quasiparticles carrying nontrivial topology., Comment: 10 pages, 8 figures

Improvements in computing performance have significantly slowed down over the past few years owing to the intrinsic limitations of computing hardware. However, the demand for data computing has increased exponentially. To solve this problem, tremendous attention has been focused on the continuous scaling of Moore's Law as well as the advanced non-von Neumann computing architecture. A rich variety of unconventional computing paradigms has been raised with the rapid development of nanoscale devices. Magnetic skyrmions, spin swirling quasiparticles, have been endowed with great expectations for unconventional computing due to their potential as the smallest information carriers by exploiting their physics and dynamics. In this paper, we provide an overview of the recent progress of skyrmion-based unconventional computing from a joint device-application perspective. This paper aims to build up a panoramic picture, analyze the remaining challenges, and most importantly to shed light on the outlook of skyrmion based unconventional computing for interdisciplinary researchers., Comment: 9 Figure, 1 Table

Electrical manipulation of skyrmions attracts considerable attention for its rich physics and promising applications. To date, such a manipulation is realized mainly via spin-polarized current based on spin-transfer torque or spin-orbital torque effect. However, this scheme is energy-consuming and may produce massive Joule heating. To reduce energy dissipation and risk of heightened temperatures of skyrmion-based devices, an effective solution is to use electric field instead of current as stimulus. Here, we realize an electric-field manipulation of skyrmions in a nanostructured ferromagnetic/ferroelectrical heterostructure at room temperature via an inverse magneto-mechanical effect. Intriguingly, such a manipulation is non-volatile and exhibits a multi-state feature. Numerical simulations indicate that the electric-field manipulation of skyrmions originates from strain-mediated modification of effective magnetic anisotropy and Dzyaloshinskii-Moriya interaction. Our results open a direction for constructing low-energy-dissipation, non-volatile, and multi-state skyrmion-based spintronic devices., Accepted by Nature Communications 11, 3577 (2020)

Magnetic skyrmions are vortex-like spin textures with nontrivial spin topology and novel physical properties that show promise as an essential building block for novel spintronic applications. Skyrmions in synthetic antiferromagnets (SAF) have been proposed long-term to have many advantages than those in ferromagnetic materials, which suffer from fundamental limits for size and efficient manipulation. Thus, experimental realization of skyrmions in SAF is intensely pursued. Here we show the observation of zero-field stable magnetic skyrmions at room temperature in SAF [Co/Pd]/Ru/[Co/Pd] multilayers with Lorentz transmission electron microscope, where uncompensated moments of the SAF provide a medium for the skyrmion characterization. Isolated skyrmions and high-density skyrmions via magnetic field and electromagnetic coordinated methods have been observed, respectively. These created high-density skyrmions maintain at zero-field even when both the current and magnetic field are removed. The use of skyrmions in SAF would advance the process toward practical nonvolatile memories based on spin topology.

Magnetic skyrmions are topologically protected spin textures that have nanoscale dimensions and can be manipulated by an electric current. These properties make the structures potential information carriers in data storage, processing and transmission devices. However, the development of functional all-electrical electronic devices based on skyrmions remains challenging. Here we show that the current-induced creation, motion, detection and deletion of skyrmions at room temperature can be used to mimic the potentiation and depression behaviours of biological synapses. In particular, the accumulation and dissipation of magnetic skyrmions in ferrimagnetic multilayers can be controlled with electrical pulses to represent the variations in the synaptic weights. Using chip-level simulations, we demonstrate that such artificial synapses based on magnetic skyrmions could be used for neuromorphic computing tasks such as pattern recognition. For a handwritten pattern dataset, our system achieves a recognition accuracy of ~89%, which is comparable to the accuracy achieved with software-based ideal training (~93%). The electrical current-induced creation, motion, detection and deletion of skyrmions in ferrimagnetic multilayers can be used to mimic the behaviour of biological synapses, providing devices that could be used for neuromorphic computing tasks such as pattern recognition.

Since the turn of the millennium, the information technology (IT) industry has been growing rapidly in mainland China. One of the significant characteristics of IT employees in mainland China during the past decades was that they tended to work more overtime, which might result in more work-family conflicts and higher turnover rates. Our study tested the mechanism of work-family conflict and work withdrawal behaviors using data from 389 IT employees in mainland China. Using the job demands-resources model and the conservation of resources theory, we examined the mediating effect of emotional exhaustion and the moderating effect of job autonomy. The results indicated that work-to-family conflict was negatively related with work withdrawal behaviors, whereas family-to-work conflict was positively related with work withdrawal behaviors. Moreover, we found the opposite moderating role of job autonomy, which enhanced the relationships between emotional exhaustion and work withdrawal behaviors. That is, the relationship was stronger among employees with higher job autonomy than among those with lower job autonomy. These findings indicate that work-family conflict relates to employees' psychological well-being and behavior, and that job autonomy might play a special role between work-family conflict and work withdrawal behaviors.

A skyrmion in frustrated magnetic system has the helicity degree of freedom. A skyrmion string is formed in a frustrated layered system, which is well described by the $XY$ model owing to the exchange coupling between adjacent layers. We consider a system where the interlayer exchange couplings are alternating, where the dimerized $XY$ model is materialized, whose linear limit is the Su-Schrieffer-Heeger model. We argue that it is a nonlinear topological system. We study the quench dynamics of the helicity wave under the initial condition that the helicity of the skyrmion in the bottommost layer is rotated. It yields a good signal to detect whether the system is topological or trivial. Our results show that the helicity dynamics of the skyrmion string have a rich physics in the modulated exchange-coupled system., 7 pages, 6 figures

Magnetic bimerons are topologically nontrivial spin textures in in-plane easy-axis magnets, which can be used as particle-like information carriers. Here, we report a theoretical study on the nonreciprocal dynamics of asymmetrical ferrimagnetic (FiM) bimerons induced by spin currents. The FiM bimerons have the ability to move at a speed of kilometers per second and do not show the skyrmion Hall effect at the angular momentum compensation point. Our micromagnetic simulations and analytical results demonstrate that spin currents are able to induce the nonreciprocal transport and a drift motion of the FiM bimeron even if the system is at the angular momentum compensation point. By analyzing the current-induced effective fields, we find that the nonreciprocal transport is attributed to the asymmetry of the bimeron structure. Our results are useful for understanding the physics of bimerons in ferrimagnets and may provide guidelines for building bimeron-based spintronic devices., Comment: 7 pages, 4 figures

Skyrmions in frustrated magnets have the helicity degree of freedom, where two different configurations of Bloch-type skyrmions are energetically favored by the magnetic dipole-dipole interaction and characterized by opposite helicities. A skyrmion must become a quantum-mechanical object when its radius is of the order of nanometer. We construct a qubit based on the two-fold degeneracy of the Bloch-type nanoscale skyrmions in frustrated magnets. It is shown that the universal quantum computation is possible based on nanoscale skyrmions in a multilayered system. We explicitly show how to construct the $\pi /4$ phase-shift gate, the Hadamard gate, and the CNOT gate. The one-qubit quantum gates are materialized by temporally controlling the electric field and the spin current. The two-qubit gate is materialized with the use of the Ising-type exchange coupling by controlling the distance between the skyrmion centers in two adjacent layers. The merit of the present mechanism is that an external magnetic field is not necessary. Our results may open a possible way toward universal quantum computations based on nanoscale topological spin textures., Comment: 7 pages, 4 figures

In times of uncertainty, such as during COVID-19, many organizations experience profit decline, and employees develop a fear of external threats, such as organizational layoffs. However, most of the literature focuses on how people’s fear influences their well-being. Less is known about how employees’ fear of external threats influences their workplace behaviors. The current study proposes that supervisors’ fear of external threats stimulates those who are high in trait anger to behave in a more abusive way. Simultaneously, subordinates’ fear of external threats would strengthen the positive relationship between abusive supervision and their burnout and compulsory citizenship behaviors (CCB), as fear of external threats constrains their response options to abusive supervision. We tested the hypotheses with a multiwave and multisource survey study (N = 322 dyads) in China, and the results showed that supervisors’ fear of external threats strengthened the positive effect of trait anger on abusive supervision. Subordinates’ fear of external threats strengthens the positive relationships of abusive supervision with CCB and the mediating effect of abusive supervision in the relationship of supervisors’ trait anger with subordinates’ CCB. Our study enriches people’s understanding of how supervisors’ and subordinates’ fear of external threats may play roles in workplace behaviors.

Magnetic skyrmions are topological swirling spin configurations that hold promise for building future magnetic memories and logic circuits. Skyrmionic devices typically rely on the electrical manipulation of a single skyrmion, but controllably manipulating a group of skyrmions can lead to more compact and memory-efficient devices. Here, an electric-field-driven cascading transition of skyrmion clusters in a nanostructured ferromagnetic/ferroelectric multiferroic heterostructure is reported, which allows a continuous multilevel transition of the number of skyrmions in a one-by-one manner. Most notably, the transition is non-volatile and reversible, which is crucial for multi-bit memory applications. Combined experiments and theoretical simulations reveal that the switching of skyrmion clusters is induced by the strain-mediated modification of both the interfacial Dzyaloshinskii-Moriya interaction and effective uniaxial anisotropy. The results not only open up a new direction for constructing low-power-consuming, non-volatile, and multi-bit skyrmionic devices, but also offer valuable insights into the fundamental physics underlying the voltage manipulation of skyrmion clusters.

Magnetic skyrmions are topological spin textures promising for future high-density and nonvolatile memory. It is crucial to understand the current-driven skyrmion dynamics in the presence of deformation, of which an analytical model, however, remains elusive. Here we extend Thiele's model by considering both the radial and tangential forces. Our model attributes the skyrmion deformation to the current-induced rotational symmetry breaking, which includes magnetization canting and domain wall width variation. Our predictions of skyrmion radius and nonlinear dynamics are consistent with micromagnetic simulation results. Besides, we show that by applying an in-plane magnetic field, the deformation of a skyrmion can be suppressed, and even the compression of a skyrmion can be achieved. Our model provides a generic way to analyze the skyrmion deformation and may inspire applications based on nonlinear skyrmion dynamics., accepted by Physical Review Applied

Frustrated topological spin textures have unique properties that may enable novel spintronic applications, such as helicity-based information storage and computing. Here, we report the statics and current-induced dynamics of two-dimensional (2D) pancake skyrmions in a stack of weakly coupled frustrated magnetic monolayers, which form a three-dimensional (3D) skyrmion string. The Bloch-type skyrmion string is energetically more stable than its N\'eel-type counterpart. It can be driven into translational motion by the dampinglike spin-orbit torque and shows the damping-dependent skyrmion Hall effect. Most notably, the skyrmion string can be transformed to a dynamically stable bimeron string by the dampinglike spin-orbit torque. The current-induced bimeron string rotates stably with respect to its center, which can spontaneously transform back to a skyrmion string when the current is switched off. Our results reveal unusual physical properties of 3D frustrated spin textures, and may open up different possibilities for spintronic applications based on skyrmion and bimeron strings., Comment: 6 pages, 3 figures

Topological spin textures can serve as non-volatile information carriers. Here we study the current-induced dynamics of an isolated magnetic skyrmion on a nanoscale square-grid pinning pattern formed by orthogonal defect lines with reduced magnetic anisotropy. The skyrmion on the square grid can be pixelated with a quantized size of the grid. We demonstrate that the position, size, and shape of skyrmion on the square grid are electrically configurable. The skyrmion center is quantized to be on the grid and the skyrmion may show a hopping motion instead of a continuous motion. We find that the skyrmion Hall effect can be perfectly prohibited due to the pinning effect of the grid. The pixelated skyrmion can be harnessed to build future programmable racetrack memory, multistate memory, and logic computing device. Our results will be a basis for digital information storage and computation based on pixelated topological spin textures on artificial pinning patterns., 27 pages, 6 figures

CeO2, TiO2, and CeO2–TiO2 layered thin films of different compositions were deposited on polished fused silica glass substrates using spin coating and then annealed at 550 °C for 1 h. Poorly crystalline fluorite-type CeO2 and anatase-type TiO2 were the only phases detected. The valence effects for Ce are attributed to intervalence charge transfer (IVCT) while those for TiO2 are attributed to simultaneous Ti4+ → Ti3+ redox and IVCT. Contamination of the grain boundaries by Si from the substrate is likely to have contributed to blockage of surface-active sites. While the roughnesses of the former thin films exhibited the expected direct correlation with the grain size, those of the latter two types of thin films showed a converse relation, suggesting that the grain boundaries of the layered TiO2 thin films included a recrystallized CeO2–TiO2 invariant point liquid and/or a CeO2–TiO2–SiO2 glass. These would have derived from the other sources of grain boundary contamination, which are Si contamination from the substrate and/or exsolved CeO2 beyond the solubility limit of TiO2. The UV–Vis spectra demonstrated two principal types of curves, with the CeO2 and higher TiO2 concentration giving typical spectra with sharp absorption edges while those of the lower TiO2 concentration indicated highly defective nanostructures with diffuse absorption edges. These data support the conclusion that CeO2 initially decreases the Eg by enhancing nucleation and recrystallization through defect formation but subsequently increases the Eg through supersaturation and consequent lattice distortion. The CeO2 thin films exhibited much worse photocatalytic performances than those of the TiO2 thin films, although no significant differences between the TiO2 thin films and the CeO2–TiO2 layered thin films were apparent, which probably resulted from the competing effects of blockage of the active sites on the grain boundaries and the extent of recrystallization of the thin film phases, the latter of which is more significant.

Racetrack memory (RM), a new storage scheme in which information flows along a nanotrack, has been considered as a potential candidate for future high-density storage device instead of hard disk drive (HDD). The first RM technology, which was proposed in 2008 by IBM, relies on a train of opposite magnetic domains separated by domain walls (DWs), named DW-RM. After 10 years of intensive research, a variety of fundamental advancements has been achieved; unfortunately, no product has been available until now. With increasing effort and resources dedicated to the development of DW-RM, it is likely that new materials and mechanisms will soon be discovered for practical applications. However, new concepts might also be on the horizon. Recently, an alternative information carrier, magnetic skyrmion, which was experimentally discovered in 2009, has been regarded as a promising replacement of DW for RM, named skyrmion-based RM (SK-RM). Intensive effort has been involved and amazing advances have been made in observing, writing, manipulating, and deleting individual skyrmions. So, what is the relationship between DW and skyrmion? What are the key differences between DW and skyrmion, or between DW-RM and SK-RM? What benefits could SK-RM bring and what challenges need to be addressed before application? In this review article, we intend to answer these questions through a comparative cross-layer study between DW-RM and SK-RM. This work will provide guidelines, especially for circuit and architecture researchers on RM.

This paper investigates disparities in subjective wellbeing in China by analyzing the Chinese General Social Survey (2003–2015). Our hierarchical age-period-cohort models reveal how Chinese Communi...

Recently, N2O, CO2, and CH4 have been gaining attention as major greenhouse gases (GHGs) that contribute to global warming. Agricultural water-saving irrigation technology has become more and more important and is widely applied to the arid areas. These influences have important and strategic significances for reducing greenhouse effects. However, there is limit information regarding the influence of irrigation methods on soil gases emissions. We investigated the effect of mulched drip irrigation (MDI), drip filtration irrigation (DFI), and conventional irrigation (CK) on N2O, CO2, CH4 emissions, affecting factors and their correlations in a greenhouse soil. Observations were performed from April to August in 2015 on the entire tomato growth season. We monitored the flux of GHG emissions by the static chamber-gas chromatograph method under three irrigation conditions: mulched drip irrigation (MDI), drip filtration irrigation (DFI), and conventional irrigation (CK). To investigate the effects of affecting factors on soil GHG emissions, we also measured soil temperature (5 cm), soil moisture, and air temperature. Compared with the cumulative emission of GHGs (N2O and CH4 calculation in the form of CO2), we created the concept of the ratio of yield and gas (crop yield and soil accumulated GHG emissions). Tomato yield of MDI and DFI is significantly higher than CK. Soil moisture is the main factor affecting N2O emissions and CH4 exchange during the tomato-growing season. N2O emission fluxes have an extremely significant correlation with water-filled pore space (WFPS) at suitable temperatures. CO2 emissions demonstrated a significant correlation with environment temperature (soil and air). CO2 emissions gradually increased and had seasonal variations with rising temperatures and plant growth in each irrigation method. CH4 exchange fluxes showed a significant correlation with WFPS. MDI obtains high yields, is cost-efficient, conserves water, and produces the least amount of integrated GHGs. It helps to mitigate global warming and it would be the best irrigation method.

In skyrmion-based racetrack memories, the information encoded by skyrmions may be destroyed due to the skyrmion Hall effect, which can be surmounted by using synthetic antiferromagnetic racetracks. Hence, the manipulation of skyrmions in synthetic antiferromagnetic racetracks is important for practical applications. Here, we computationally study the interaction between a pair of skyrmions and a locally modified region in a synthetic antiferromagnetic racetrack, where the perpendicular magnetic anisotropy or thickness is locally adjusted to be different from that of the rest region of the racetrack. It is found that the skyrmions can be attracted, repelled, and even trapped by the locally modified region in a controllable manner. Besides, we demonstrate that the skyrmion location can be precisely determined by the locally modified region. The possible manipulation of skyrmions by utilizing locally modified regions in a synthetic antiferromagnetic racetrack may be useful for future skyrmion-based applications., Comment: 5 pages, 4 figures

Mo3+- or Mo5+-doped TiO2 sol-gel thin films (≤0.100 mol%) were spin coated on fused silica glass substrates and annealed at 450 °C for 2 h. The effect of the valence of the dopant precursor is significant to the nanostructural development and resultant properties. Mo3+ or Mo5+ doping yields converse trends with doping level, thus reflecting the competing influences of lattice distortion and destabilization (dominating Mo3+ doping) and nucleation and recrystallization (dominating Mo5+ doping). Mo doping results in oxidation of Mo3+ and reduction of Mo5+, both of which alter to Mo(5−x)+, as well as oxidation of Ti3+ to Ti(4+x)+; all of these result in V O • • annihilation. Although the absorption edges were largely indistinguishable, Mo3+ doping causes a red shift and Mo5+ doping causes a blue shift. These data suggest that the performances are controlled by the synergistic effects of crystallinity, surface area, and band gap, with the latter's exhibiting the dominant effect. This suggests that the defect structure governs the photocatalytic performance but also that the defect chemistry at these low annealing temperatures is indicative of nonequilibrium conditions, thereby explaining the significance of the dopant valence.

Magnetic skyrmions are topologically protected domain structures related to the Dzyaloshinskii-Moriya interaction (DMI). To understand how magnetic skyrmions occur under different circumstances, we propose a model for skyrmion formation in a bilayer system of ferromagnetic/antiferromagnetic (FM/AFM) films, in which the bulk DMI is only present in the AFM film. Micromagnetic simulations reveal that skyrmions are formed in this system due to the competition between the DMI and demagnetization energies. A critical interfacial exchange energy (Ai = 6.5 mJ/m2) is determined, above which the competition occurs at its full extent. More skyrmions are formed with increasing external magnetic field till a critical value above which the external field is too large and thus leading to the annihilation of skyrmions. The spacing between two skyrmions can be as small as 45 nm. Our results may give technological implications for future skyrmion applications.

Topological spin textures can be found in both two-dimensional and three-dimensional nanostructures, which are of great importance to advanced spintronic applications. Here we report the current-induced skyrmion tube dynamics in three-dimensional synthetic antiferromagnetic (SyAF) bilayer and multilayer nanostructures. It is found that the SyAF skyrmion tube made of thinner sublayer skyrmions is more stable during its motion, which ensures that a higher speed of the skyrmion tube can be reached effectively at larger driving current. In the SyAF multilayer with a given total thickness, the current-induced deformation of the SyAF skyrmion tube decreases with an increasing number of interfaces; namely, the rigidity of the SyAF skyrmion tube with a given thickness increases with the number of ferromagnetic (FM) layers. For the SyAF multilayer with an even number of FM layers, the skyrmion Hall effect can be eliminated when the thicknesses of all FM layers are identical. Larger damping parameter leads to smaller deformation and slower speed of the SyAF skyrmion tube. Larger fieldlike torque leads to larger deformation and a higher speed of the SyAF skyrmion tube. Our results are useful for understanding the dynamic behaviors of three-dimensional topological spin textures and may provide guidelines for building SyAF spintronic devices., Comment: 8 pages, 6 figures

Magnetic skyrmions are potential building blocks for future information storage and computing devices. Here, we computationally study the skyrmion dynamics in a cross structure made of two ferromagnetic nanotracks. We show that by controlling the skyrmion motion in the cross structure using spin currents, it is possible to realize the transcription of skyrmion at the intersection of the cross structure at certain conditions. Based on the transcription of skyrmion, we computationally demonstrate the AND, OR and NOT logical gates using the cross structures with modified geometries and appropriate magnetic parameters. Our results may provide guidelines to design future three-dimensional spintronics devices based on magnetic skyrmions.

The advent of ferromagnetism in two-dimensional (2D) van der Waals (vdW) magnets has stimulated high interest in exploring topological magnetic textures, such as skyrmions for use in future skyrmion-based spintronic devices. To engineer skyrmions in vdW magnets by transforming Bloch-type magnetic bubbles into N\'eel-type skyrmions, the heterostructure of heavy metal/vdW magnetic thin film has been made to induce interfacial Dzyaloshinskii-Moriya interaction (DMI). However, the unambiguous identification of the magnetic textures inherent to vdW magnets, e.g., whether the magnetic twists (skyrmions/domain walls) are N\'eel- or Bloch-type, is unclear. Here we demonstrate that the N\'eel- or Bloch-type magnetic twists can be tuned in the vdW magnet Fe3GeTe2 (FGT) with/without interfacial DMI. We use an in-plane magnetic field to align the modulation wavevector q of the magnetizations in order to distinguish the N\'eel- or Bloch-type magnetic twists. We observe that q is perpendicular to the in-plane field in the heterostructure (Pt/oxidized-FGT/FGT/oxidized-FGT), while q aligns at a rotated angle with respect to the field direction in the thin plate by thinning bulk FGT. We find that the aligned domain wall twists hold fan-like modulations, coinciding qualitatively with our computational results.

Topological spin textures have been an extremely hot topic since their first experimental observation in 2009 [...]

Perpendicular magnetization switching driven by spin–orbit torques plays an increasingly important role for spintronic devices toward practical applications but is also hindered by the well-known technical challenge that an external in-plane magnetic field is required for deterministic switching. Here, we show that the deterministic switching can be achieved in synthetic antiferromagnets through the flexible domain control in the absence of external magnetic fields. Specifically, we have observed that the domain wall (DW) distorts under an applied electric current in contrast to the conventional rigid DW motion in a single ferromagnet. More importantly, the distorted DWs can be precisely controlled under zero magnetic field, leading to the deterministic switching. Our results indicate that the critical technical challenge may be addressed by employing a synthetic antiferromagnetic layer through the DW motion dominated field-free switching.

Supplemental material, sj-pdf-1-pac-10.1177_18344909211010514 for Psychological Capital, Positive Affect, and Organizational Outcomes by Shu Da, Ze Zhu, Hongyu Cen, Xianmin Gong, Oi Ling Siu and Xichao Zhang in Journal of Pacific Rim Psychology

In this chapter, we introduce the concept of magnetic skyrmions in ferrimagnetic materials. We also review and discuss recent findings and advances in the field of ferrimagnetic skyrmions. In particular, we focus on the theoretical and experimental works regarding the writing, deleting, imaging, and detection of ferrimagnetic skyrmions that are key ingredients for future applications. We also introduce and discuss the current-induced dynamics of ferrimagnetic skyrmions, including the associated skyrmion Hall effect in ferrimagnets. Finally, we briefly review potential applications based on ferrimagnetic skyrmions. The special fully compensated case of ferrimagnetic skyrmions, that is, the antiferromagnetic skyrmions, will be reviewed in detail in Chapter 10.

In this chapter, we focus on possible conventional applications based on the manipulation of magnetic skyrmions. We will review skyrmion-based racetrack memory device concepts, including both single layer and multilayer systems. We will also introduce and review the concept of using skyrmions for conventional logic computing. Besides, we will review skyrmion-based transistor-like functional devices and skyrmion-based nano-oscillator devices. In addition, we will review and discuss the electric-field control of skyrmion for future applications. This chapter will be ended with a brief summary on proposed concepts of conventional skyrmion-based applications and possible skyrmion-based applications that can be further studied in the following years.

Supplemental material, sj-pdf-1-pac-10.1177_18344909211010514 for Psychological Capital, Positive Affect, and Organizational Outcomes by Shu Da, Ze Zhu, Hongyu Cen, Xianmin Gong, Oi Ling Siu and Xichao Zhang in Journal of Pacific Rim Psychology

The topological spin textures, such as magnetic skyrmions and bimerons, are currently a hot topic in condensed matter physics. Magnetic skyrmions are swirling spin textures, which can be stabilized in chiral magnets with perpendicular magnetic anisotropy, while magnetic bimerons can be regarded as the counterpart of skyrmions in magnetic systems with in-plane anisotropy. Both magnetic skyrmions and bimerons have attracted a lot of attentions, because they have small size and low depinning current, and can be used as nonvolatile information carries in future spintronic devices. In this chapter, we mainly present and discuss recent original results about the magnetization dynamics of antiferromagnetic skyrmions and bimerons excited by currents and spatially non-uniform magnetic anisotropy. In addition, we also explore possible applications based on antiferromagnetic skyrmions and bimerons, and review some relevant results.

Magnetic skyrmionium is a skyrmion-like spin texture with nanoscale size and high mobility. It is a topologically trivial but dynamically stable structure, which can be used as a non-volatile information carrier for next-generation spintronic storage and computing devices. Here, we study the dynamics of a skyrmionium driven by the spin torque in a ferrimagnetic nanotrack. It is found that the direction of motion is jointly determined by the internal configuration of a skyrmionium and the spin polarization vector. Besides, the deformation of a skyrmionium induced by the intrinsic skyrmion Hall effect depends on both the magnitude of the driving force and the net angular momentum. The ferrimagnetic skyrmionium is most robust at the angular momentum compensation point, whose dynamics is quite similar to the skyrmionium in antiferromagnet. The skyrmion Hall effect is perfectly prohibited, where it is possible to observe the position of the skyrmionium by measuring the magnetization. Furthermore, the current-induced dynamics of a ferrimagnetic skyrmionium is compared with that of a ferromagnetic and antiferromagnetic skyrmionium. We also make a comparison between the motion of a ferrimagnetic skyrmionium and a skyrmion. Our results will open a new field of ferrimagnetic skyrmioniums for future development of ferrimagnetic spintronics devices.

Based on the analysis of control system software automatic test language requirements, this paper proposes a Python-based automatic test language for control system software, which abstractly models the test behavior logic to form a general test script model library and a dedicated test script model library. Testers can write test case scripts by calling the existing test script model, or they can supplement the existing test behavior logic according to the actual test requirements to form a more convenient test script model. The test language can accurately, efficiently and flexibly describe the software testing behavior of the control system, and has the characteristics of easy to master, low test cost, and flexible application. Through the application in the automatic test of spacecraft control software in different fields, the results show that using this test language can execute test cases completely and accurately, which improves the test efficiency and realizes the universalization of the test language.

Magnetic skyrmionium can be used as a nanometer-scale non-volatile information carrier, which shows no skyrmion Hall effect due to its special structure carrying zero topological charge. Here, we report the static and dynamic properties of an isolated nanoscale skyrmionium in a frustrated magnetic monolayer, where the skyrmionium is stabilized by competing interactions. The frustrated skyrmionium has a size of about $10$ nm, which can be further reduced by tuning perpendicular magnetic anisotropy or magnetic field. It is found that the nanoscale skyrmionium driven by the damping-like spin-orbit torque shows directional motion with a favored Bloch-type helicity. A small driving current or magnetic field can lead to the transformation of an unstable N\'eel-type skyrmionium to a metastable Bloch-type skyrmionium. A large driving current may result in the distortion and collapse of the Bloch-type skyrmionium. Our results are useful for the understanding of frustrated skyrmionium physics, which also provide guidelines for the design of spintronic devices based on topological spin textures., Comment: 5 pages, 5 figures

Magnetic bimeron is a topological counterpart of skyrmions in in-plane magnets, which can be used as a spintronic information carrier. We report the static properties of bimerons with different topological structures in a frustrated ferromagnetic monolayer, where the bimeron structure is characterized by the vorticity $Q_{\text{v}}$ and helicity $\eta$. It is found that the bimeron energy increases with $Q_{\text{v}}$, and the energy of an isolated bimeron with $Q_{\text{v}}=\pm 1$ depends on $\eta$. We also report the dynamics of frustrated bimerons driven by the spin-orbit torques, which depend on the strength of the dampinglike and fieldlike torques. We find that the isolated bimeron with $Q_{\text{v}}=\pm 1$ can be driven into linear or elliptical motion when the spin polarization is perpendicular to the easy axis. We numerically reveal the damping dependence of the bimeron Hall angle driven by the dampinglike torque. Besides, the isolated bimeron with $Q_{\text{v}}=\pm 1$ can be driven into rotation by the dampinglike torque when the spin polarization is parallel to the easy axis. The rotation frequency is proportional to the driving current density. In addition, we numerically demonstrate the possibility of creating a bimeron state with a higher or lower topological charge by the current-driven collision and merging of bimeron states with different $Q_{\text{v}}$. Our results could be useful for understanding the bimeron physics in frustrated magnets., Comment: 13 pages, 12 figures

Henan province is one of the most critical emitters of ammonia (NH3) and is one of the most seriously air polluted regions in China. In this study, we developed a first comprehensive and novel 2015-based NH3 emission inventory for Henan province based on investigational activity data with corrected and updated emission factors of anthropogenic and natural sources. The 3 km × 3 km gridded emissions and monthly variations were allocated by using appropriate spatial and localized temporal surrogates. The total NH3 emission was 1031.6 Gg in 2015, of which livestock, N fertilizer application, and humans were the top three contributors, accounting for 57.3%, 28.2%, and 3.1%, respectively. The cities of Nanyang, Zhoukou, and Zhumadian with more rural and agricultural activities were demonstrated to have relatively high emissions, accounting for 12.5%, 10.1%, and 9.7% of total emissions, respectively. The regional averaged emission density was 6.3 t km−2, with higher values in eastern and northern Henan province. Obvious seasonal variability was observed, with the highest emission in July and the lowest in January associated with temperature and local farming activities. In addition, according to the emissions investigation carried out from 2006 to 2016, the largest changes occurred in non-agricultural sources. Furthermore, we quantitatively analyzed the estimated emissions with the uncertainty range of -33%-35% using the AuvToolPro tool. This emission inventory was also evaluated by comparing the magnitudes with other studies, analyzing the correlation of the observed ambient NH3 concentration with emission density and temperature, and investigating the trend of molar ratio of (2SO2+NO2)/NH3. The emission inventory developed in this study can provide information to understand local emission characteristics, and to determine how to prioritize effective control strategies properly for policy makers.

Magnetic skyrmion (Sk), instead of magnetic domain wall (DW), holds great promise as alternative information carriers in the future ultradense and low-power racetrack memory (RM). More importantly, by exploiting its unique properties, such as particle-like behavior and topological stability, Sk enables new functionalities that may be inaccessible to DW in RM applications. In this paper, we propose a complementary Sk-RM structure that enables voltage-controlled local data update functionality. Similar to our previous design in addressing the data representation issue, data information is represented in a robust way that both “0” and “1” are represented in the form of Sks and are moved synchronously by the spin Hall effect. Furthermore, this complementary Sk-RM structure can be developed for enabling local data update functionality, because Sks can be shifted between the two nanotracks by regulating the voltage-controlled gates. In this case, data bits “0” and “1” can be converted to each other freely within the nanotrack without being moved out of the nanotrack. This functionality brings great benefits in data access and management. Functionality and performance of the proposed design are studied with micromagnetic simulations.