1,940 research outputs found

    Crystallographic and superconducting properties of the fully-gapped noncentrosymmetric 5d-electron superconductors CaMSi3 (M=Ir, Pt)

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    We report crystallographic, specific heat, transport, and magnetic properties of the recently discovered noncentrosymmetric 5d-electron superconductors CaIrSi3 (Tc = 3.6 K) and CaPtSi3 (Tc = 2.3 K). The specific heat suggests that these superconductors are fully gapped. The upper critical fields are less than 1 T, consistent with limitation by conventional orbital depairing. High, non-Pauli-limited {\mu}0 Hc2 values, often taken as a key signature of novel noncentrosymmetric physics, are not observed in these materials because the high carrier masses required to suppress orbital depairing and reveal the violated Pauli limit are not present.Comment: 8 pages, 8 figure

    Large spin-orbit splitting and weakly-anisotropic superconductivity revealed with single-crystalline noncentrosymmetric CaIrSi3

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    We report normal and superconducting properties of the Rashba-type noncentrosymmetric com- pound CaIrSi3, using single crystalline samples with nearly 100% superconducting volume fraction. The electronic density of states revealed by the hard x-ray photoemission spectroscopy can be well explained by the relativistic first-principle band calculation. This indicates that strong spin-orbit interaction indeed affects the electronic states of this compound. The obtained H - T phase diagram exhibits only approximately 10% anisotropy, indicating that the superconducting properties are almost three dimensional. Nevertheless, strongly anisotropic vortex pinning is observed.Comment: 8 pages, 6 figures, 1 table, accepted for publication in Phys. Rev.

    Quantitative analysis of the kinematics of the foot during gait with respect to barefoot running shoes using a Multi-Segment Foot Model

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    Kinematics of the foot during static and dynamic tasks are technically challenging to accurately measure, making it difficult to evaluate their contribution to running-related injuries. Motion capture can detect changes in running mechanics, such as with differing footwear. Habitual barefoot runners and/habitual minimalist shoe runners underwent a biomechanical evaluation of their foot movement during running using reflective markers and optical motion capture. A five-segment foot model was used to compare motions between the different parts of the foot while running barefoot and wearing Vibram Five Fingers™ (VFF) barefoot mimicking shoes. Supination/pronation in the forefoot was larger but not significant between habitual shod and habitual VFF runners. In contrast, the other foot motions (forefoot spreading/rising, hindfoot pronation/supination and hindfoot adduction/abduction) were not significantly different between the groups of runners. Therefore it could be possible that transitioning from a regular running shoe to a barefoot mimicking minimalist shoe would cause the foot to adopt a more supinated gait cycle

    Elastic properties of the Non-Fermi liquid metal CeRu4Sb12Ce Ru_4 Sb_{12} and the Dense Kondo semiconductor CeOs4Sb12Ce Os_4 Sb_{12}

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    We have investigated the elastic properties of the Ce-based filled skutterudite antimonides CeRu4_{4}Sb12_{12} and CeOs4_{4}Sb12_{12} by means of ultrasonic measurements. CeRu4_{4}Sb12_{12} shows a slight increase around 130 K in the temperature dependence of the elastic constants CC11_{11}, (CC11_{11}-CC12_{12})/2 and CC44_{44}. No apparent softening toward low temperature due to a quadrupolar response of the 4ff-electronic ground state of the Ce ion was observed at low temperatures. In contrast CeOs4_{4}Sb12_{12} shows a pronounced elastic softening toward low temperature in the longitudinal CC11_{11} as a function of temperature (TT) below about 15 K, while a slight elastic softening was observed in the transverse CC44_{44} below about 1.5 K. Furthermore, CeOs4_{4}Sb12_{12} shows a steep decrease around a phase transition temperature of 0.9 K in both CC11_{11} andC C44_{44}. The elastic softening observed in CC11_{11} below about 15 K cannot be explained reasonably only by the crystalline electric field effect. It is most likely to be responsible for the coupling between the elastic strain and the quasiparticle band with a small energy gap in the vicinity of Fermi level. The elastic properties and the 4ff ground state of Ce ions in CeRu4_{4}Sb12_{12} and CeOs4_{4}Sb12_{12} are discussed from the viewpoint of the crystalline electric field effect and the band structure in the vicinity of Fermi level.Comment: 9 pages, 11 figures, regular pape
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