11,964 research outputs found

    Cluster spin-glass ground state in quasi-one-dimensional KCr3_{3}As3_{3}

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    We report structural and physical properties of a new quasi-one-dimensional Cr-based compound, KCr3_{3}As3_{3}, which is prepared by potassium deintercalation from the superconductive K2_{2}Cr3_{3}As3_{3}. KCr3_{3}As3_{3} adopts the TlFe3_{3}Te3_{3}-type structure with space group P63P6_{3}/mm (No. 176). The high-temperature magnetic susceptibility obeys the Curie-Weiss law with an effective magnetic moment of 0.68 μB\mu_{\mathrm{B}}/Cr. Below 56 K the susceptibility deviates from the high-temperature Curie-Weiss behavior, coinciding with the rapid increase in resistivity, which suggests formation of spin clusters. The short-range spin correlations are also supported by the specific-heat data. The title material does not exhibit bulk superconductivity; instead, it shows a cluster spin-glass state below \sim 5 K.Comment: 5 pages, 4 figure

    First-Principles Investigation of Anistropic Hole Mobilities in Organic Semiconductors

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    We report a simple first-principles-based simulation model (combining quantum mechanics with Marcus−Hush theory) that provides the quantitative structural relationships between angular resolution anisotropic hole mobility and molecular structures and packing. We validate that this model correctly predicts the anisotropic hole mobilities of ruberene, pentacene, tetracene, 5,11-dichlorotetracene (DCT), and hexathiapentacene (HTP), leading to results in good agreement with experiment

    Unidirectional anisotropy in cubic FeGe with antisymmetric spin-spin-coupling

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    We report strong unidirectional anisotropy in bulk polycrystalline B20 FeGe measured by ferromagnetic resonance spectroscopy. Bulk and micron-sized samples were produced and analytically characterized. FeGe is a B20 compound with inherent Dzyaloshinskii-Moriya interaction. Lorenz microscopy confirms a skyrmion lattice at 190  K190 \; \text{K} in a magnetic field of 150 mT. Ferromagnetic resonance was measured at 276  K±1  K276 \; \text{K} \pm 1 \; \text{K}, near the Curie temperature. Two resonance modes were observed, both exhibit a unidirectional anisotropy of K=1153  J/m3±10  J/m3K=1153 \; \text{J/m}^3 \pm 10 \; \text{J/m}^3 in the primary, and K=28  J/m3±2  J/m3K=28 \; \text{J/m}^3 \pm 2 \; \text{J/m}^3 in the secondary mode, previously unknown in bulk ferromagnets. Additionally, about 25 standing spin wave modes are observed inside a micron-sized FeGe wedge, measured at room temperature (  293\sim \; 293 K). These modes also exhibit unidirectional anisotropy
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