9,090 research outputs found

    Transport and Magnetic Properties of FexVse2 (x = 0 - 0.33)

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    We present our results of the effect of Fe intercalation on the structural, transport and magnetic properties of 1T-VSe2. Intercalation of iron, suppresses the 110K charge density wave (CDW) transition of the 1T-VSe2. For the higher concentration of iron, formation of a new kind of first order transition at 160K takes place, which go on stronger for the 33% Fe intercalation. Thermopower of the FexVSe2 compounds (x = 0 - 0.33), however do not show any anomaly around the transition. The intercalation of Fe does not trigger any magnetism in the weak paramagnetic 1T-VSe2, and Fe is the low spin state of Fe3+.Comment: 7 pages, 8 figures, 2 table

    Spin-torque generation by dc or ac voltages in magnetic layered structures

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    A general expression of the current induced spin torque in a magnetic layered structure in the presence of external dc or ac voltages is derived in the framework of the scattering matrix approach. A detailed analysis is performed for a magnetic-nonmagnetic-magnetic trilayer connected to external leads in the presence of dc voltage bias in the ballistic regime. Alternatively, the possibility of producing spin torque by means of the adiabatic ac modulation of external gate voltages (quantum pumping) is proposed and discussed

    ESR Study of Optically Induced Phase Transitions

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    We have identified an optically enhanced magnetic phase transition in the newly synthesized organic molecular charge transfer salt, (BEDT-TTF)3Ta2F11 (BEDT-TTF bisethylenedithiolotetrathiafulvalene) by ESR absorption measurements in the X band microwave region. At room temperature, only a doublet state ESR absorption is observed, but below 30 K severa~ tripl~t E.SR absorpti_ons appear. The orientation dependence of the ESR absorption under lllummat10n at energies near the band gaps in the material ( 640 nm, T = 12 to 5 K H0 \u3c 0.34 T) indicates that there are rapid spin exchange processes with times r \u3c w-s; near 7 ~o 5 K.along cert~in ~rystallographic directions with a temperature dependen~e suggesting spm-lattlce relaxation times which proceed via Van Vleck direct processes. This, to our knowledge, is the first case where the magnetic properties of a charge transfer salt are altered by the interaction with photons of energy equal to the band gaps in a low dimensional solid providing a new, interesting way to investigate these materials

    Tunneling Anisotropic Magnetoresistance of Helimagnet Tunnel Junctions

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    We theoretically investigate the angular and spin dependent transport in normal-metal/helical-multiferroic/ferromagnetic heterojunctions. We find a tunneling anisotropic magnetoresistance (TAMR) effect due to the spiral magnetic order in the tunnel junction and to an effective spin-orbit coupling induced by the topology of the localized magnetic moments in the multiferroic spacer. The predicted TAMR effect is efficiently controllable by an external electric field due to the magnetoelectric coupling

    Air traffic control by distributed management in a MLS environment

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    The microwave landing system (MLS) is a technically feasible means for increasing runway capacity since it could support curved approaches to a short final. The shorter the final segment of the approach, the wider the variety of speed mixes possible so that theoretically, capacity would ultimately be limited by runway occupance time only. An experiment contrasted air traffic control in a MLS environment under a centralized form of management and under distributed management which was supported by a traffic situation display in each of the 3 piloted simulators. Objective flight data, verbal communication and subjective responses were recorded on 18 trial runs lasting about 20 minutes each. The results were in general agreement with previous distributed management research. In particular, distributed management permitted a smaller spread of intercrossing times and both pilots and controllers perceived distributed management as the more 'ideal' system in this task. It is concluded from this and previous research that distributed management offers a viable alternative to centralized management with definite potential for dealing with dense traffic in a safe, orderly and expeditious manner

    Tunable magnetization damping in transition metal ternary alloys

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    We show that magnetization damping in Permalloy, Ni80Fe20 (``Py''), can be enhanced sufficiently to reduce post-switching magnetization precession to an acceptable level by alloying with the transition metal osmium (Os). The damping increases monotonically upon raising the Os-concentration in Py, at least up to 9% of Os. Other effects of alloying with Os are suppression of magnetization and enhancement of in-plane anisotropy. Magnetization damping also increases significantly upon alloying with the five other transition metals included in this study (4d-elements: Nb, Ru, Rh; 5d-elements: Ta, Pt) but never as strongly as with Os.Comment: 4 pages, submitted to Appl. Phys. Let

    A technique for using employee perception of security to support usability diagnostics

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    Problems of unusable security in organisations are widespread, yet security managers tend not to listen to employees' views on how usable or beneficial security controls are for them in their roles. Here we provide a technique to drive management of security controls using end-user perceptions of security as supporting data. Perception is structured at the point of collection using Analytic Hierarchy Process techniques, where diagnostic rules filter user responses to direct remediation activities, based on recent research in the human factors of information security. The rules can guide user engagement, and support identification of candidate controls to maintain, remove, or learn from. The methodology was incorporated into a prototype dashboard tool, and a preliminary validation conducted through a walk-through consultation with a security manager in a large organisation. It was found that user feedback and suggestions would be useful if they can be structured for review, and that categorising responses would help when revisiting security policies and identifying problem controls

    Menu engineering to encourage sustainable food choices when dining out: An online trial of priced-based decoys

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    Menu-based ‘nudges’ hold promise as effective ways to encourage a shift away from ruminant meat and towards more environmentally friendly plant-based options when dining out. One example of a menu-based nudge is including an inferior ‘decoy’ option to existing items on menus. Decoys have been shown to influence decision-making in other domains (e.g. Lichters, Bengart, Sarstedt, & Vogt, 2017), but have yet to be used to promote sustainable food choices. Two online randomized controlled trials tested whether the addition of higher priced ‘decoy’ vegetarian options to menus influenced the number of diners choosing a ‘target’ vegetarian option. Adjusted Generalized Estimating Equations on data from four menu conditions showed no main effect of intervention group in study 1 (decoy absent vs. decoy present; odds ratio (OR) 1.08 (95% Confidence Interval (CI) 0.45 to 2.57). Replicating the trial in study 2 across seven menu conditions and testing a more expensive decoy also showed no main effect of the intervention (decoy absent vs. decoy present; OR 0.68 (95% CI 0.41 to 1.12). Further analyses revealed that our price-based decoy strategy (a £30% price increase) did not significantly influence the numbers who chose the inferior decoy dish, potentially due to the fact that dish choices were purely hypothetical. Further research is now needed to clarify which attributes of a dish (e.g. taste, portion size, signature ingredients etc.) are optimal candidates for use as decoys and testing these in real world choice contexts
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