7,805 research outputs found

    Control of tetrahedral coordination and superconductivity in FeSe0.5Te0.5 thin films

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    We demonstrate a close relationship between superconductivity and the dimensions of the Fe-Se(Te) tetrahedron in FeSe0.5Te0.5. This is done by exploiting thin film epitaxy, which provides controlled biaxial stress, both compressive and tensile, to distort the tetrahedron. The Se/Te height within the tetrahedron is found to be of crucial importance to superconductivity, in agreement with the theoretical proposal that (pi,pi) spin fluctuations promote superconductivity in Fe superconductors

    Manual for extending the laser specklegram technique to strain analysis of rotating components

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    The theory, techniques, and equipment necessary for extending laser speckle techniques to analyze stresses in rotating blades are described. Details for setting up the equipment, for timing the events, for data recording, and for data analysis are discussed. Finite element techniques are investigated for analysis of speckle data. Advantages and limitations of the finite element analysis for the speckle data are discussed. The finite element program is listed

    Antisymmetric magnetoresistance in magnetic multilayers with perpendicular anisotropy

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    While magnetoresistance (MR) has generally been found to be symmetric in applied field in non-magnetic or magnetic metals, we have observed antisymmetric MR in Co/Pt multilayers. Simultaneous domain imaging and transport measurements show that the antisymmetric MR is due to the appearance of domain walls that run perpendicular to both the magnetization and the current, a geometry existing only in materials with perpendicular magnetic anisotropy. As a result, the extraordinary Hall effect (EHE) gives rise to circulating currents in the vicinity of the domain walls that contributes to the MR. The antisymmetric MR and EHE have been quantitatively accounted for by a theoretical model.Comment: 17 pages, 4 figure

    CHARACTERISTIC GROUND REACTION FORCES IN SOFTBALL PITCHING

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    The purpose of this study was to investigate the ground reaction forces of pushing leg and landing leg during softball pitching with windmill style fastball. Four female elite fastpitch softball pitchers served as subjects. A Peak high-speed camera (120Hz) was synchronized with a force plate (600Hz) to collect the parameters of lower extremity during pitching. Results indicated that the higher impulse of pushing leg and the peak slope of landing leg improve softball pitching performance. In addition, the peak ground reaction forces appeared before the human neuromuscular system responded to modify these forces. The greater ground reaction forces created during the landing phase putting a heavy load on lower extremity. It was suggested that the improvement of lower extremities strength would reduce the injury and improve softball pitching performance

    Proper Scaling of the Anomalous Hall Effect

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    Working with epitaxial films of Fe, we succeeded in independent control of different scattering processes in the anomalous Hall effect. The result appropriately accounted for the role of phonons, thereby clearly exposing the fundamental flaws of the standard plot of the anomalous Hall resistivity versus longitudinal resistivity. A new scaling has been thus established that allows an unambiguous identification of the intrinsic Berry curvature mechanism as well as the extrinsic skew scattering and side-jump mechanisms of the anomalous Hall effect.Comment: 5 pages, 4 figure

    Zero-Bias Anomalies in Narrow Tunnel Junctions in the Quantum Hall Regime

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    We report on the study of cleaved-edge-overgrown line junctions with a serendipitously created narrow opening in an otherwise thin, precise line barrier. Two sets of zero-bias anomalies are observed with an enhanced conductance for filling factors ν>1\nu > 1 and a strongly suppressed conductance for ν<1\nu < 1. A transition between the two behaviors is found near ν1\nu \approx 1. The zero-bias anomaly (ZBA) line shapes find explanation in Luttinger liquid models of tunneling between quantum Hall edge states. The ZBA for ν<1\nu < 1 occurs from strong backscattering induced by suppression of quasiparticle tunneling between the edge channels for the n=0n = 0 Landau levels. The ZBA for ν>1\nu > 1 arises from weak tunneling of quasiparticles between the n=1n = 1 edge channels.Comment: version with edits for clarit
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