411 research outputs found

    Evolution of superconductivity in LaO1-xFxBiS2 prepared by high pressure technique

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    Novel BiS2-based superconductors LaO1-xFxBiS2 prepared by the high pressure synthesis technique were systematically studied. It was found that the high pressure annealing strongly the lattice as compared to the LaO1-xFxBiS2 samples prepared by conventional solid state reaction at ambient pressure. Bulk superconductivity was observed within a wide F-concentration range of x = 0.2 ~ 0.7. On the basis of those results, we have established a phase diagram of LaO1-xFxBiS2.Comment: 11 pages, 6 figure

    s-wave pairing in the optimally-doped LaO0.5F0.5BiS2 superconductor

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    We report on the magnetic and superconducting properties of LaO0.5F0.5BiS2 by means of zero- (ZF) and transverse-field (TF) muon-spin spectroscopy measurements (uSR). Contrary to previous results on iron-based superconductors, measurements in zero field demonstrate the absence of magnetically ordered phases. TF-uSR data give access to the superfluid density, which shows a marked 2D character with a dominant s-wave temperature behavior. The field dependence of the magnetic penetration depth confirms this finding and further suggests the presence of an anisotropic superconducting gap

    Fermiological Interpretation of Superconductivity/Non-superconductivity of FeTe_{1-x}Se_{x} Thin Crystal Determined by Quantum Oscillation Measurement

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    We have successfully observed quantum oscillation (QO) for FeTe_{1-x}Se_{x}. QO measurements were performed using non-superconducting and superconducting thin crystals of FeTe_{0.65}Se_{0.35} fabricated by the scotch-tape method. We show that the Fermi surfaces (FS) of the non-superconducting crystal are in good agreement with the rigid band shift model based on electron doping by excess Fe while that of the superconducting crystal is in good agreement with the calculated FS with no shift. From the FS comparison of both crystals, we demonstrate the change of the cross-sectional area of the FS, suggesting that the suppression of the FS nesting with the vector Q_{s} = (\pi, \pi) due to excess Fe results in the disappearance of the superconductivity.Comment: 8 pages, 4 figure

    Comparative dynamics of self-consciousness of schizophrenic patients and patients with acute and transient psychotic disorders in the process of compulsory treatment.

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    Article presents the materials of empirical research of life sense orientations, self-relation and level of claims of schizophrenic patients and patients with acute and transient psychotic disorders, who have committed socially hazardous actions and to whom forced measures of medical character are temporarily applied. Changes in the self- consciousness of patients with schizophrenia in dynamics were examined: in com­paring the results obtained at first and fourth stages of patients' stay in mental hospital with strict supervision (the first stage – adaptation and diagnostics, the fourth stage – the consolidation of treatment results and preparation of patient to be discharged). Research was done by D. Leontiev’s test of life sense orientations (LSO), by S. Pantileyev – V. Sto­lin’s techniques and by Shwarzlander’s “Motor test”. Statistical processing of the obtained results of differences by indices of life sense orientations, of selfattitude and level of claims between the group under study with Student's t-criterion was used
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