122 research outputs found

    Prevalence of major levator abnormalities in symptomatic patients with an underactive pelvic floor contraction

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    Introduction and hypothesis: Major levator ani abnormalities (LAA) may lead to abnormal pelvic floor muscle contraction (pfmC) and secondarily to stress urinary incontinence (SUI), prolapse, or fecal incontinence (FI). Methods: A retrospective observational study included 352 symptomatic patients to determine prevalence of LAA in underactive pfmC and the relationship with sympt

    Enhancement of spin orbit coupling at manganite surfaces

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    Spin orbit coupling in magnetic systems lacking inversion symmetry can give rise to nontrivial spin textures. Magnetic thin films and heterostructures are potential candidates for the formation of skyrmions and other noncollinear spin configurations as inversion symmetry is inherently lost at their surfaces and interfaces. However, manganites, in spite of their extraordinarily rich magnetic phase diagram, have not yet been considered of interest within this context as their spin orbit coupling is assumed to be negligible. We demonstrate here, by means of angular dependent x ray linear dichroism experiments and theoretical calculations, the existence of a noncollinear antiferromagnetic ordering at the surface of ferromagnetic La2 3Sr1 3MnO3 thin films whose properties can only be explained by an unexpectedly large enhancement of the spin orbit interaction. Our results reveal that spin orbit coupling, usually assumed to be very small in manganites, can be significantly enhanced at surfaces and interfaces adding a new twist to the possible magnetic orders that can arise in electronically reconstructed system

    Interfacial effects in La 2/3 Sr 1/3 MnO 3 thin films with different complex oxide capping layers

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    Interfacial effects in sputtered La 2/3 Sr 1/3 MnO 3 thin films with different capping layers (MgO, LaAlO 3 , SrTiO 3 , NdGaO 3 , and Au) have been locally investigated by means of x-ray absorption spectroscopy and x-ray magnetic circular dichroism at the Mn L 3,2 -edge. Data were acquired by using the total electron yield detection mode thus guaranteeing maximum sensitivity to the interface. The data show that LaAlO 3 capping almost does not modify the bulklike Mn valence at the interface. In case of SrTiO 3 and Au, the presence of divalent Mn is detected, whereas MgO and NdGaO 3 capping lead to an increase of the Mn valence oxidation state. The modification of the nominal Mn valence state leads to depressed surface magnetization

    Anomalous electronic susceptibility in Bi2Sr2CuO6+d and comparison with other overdoped cuprates

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    We report magnetic susceptibility performed on overdoped Bi2Sr2CuO6+d powders as a function of oxygen doping d and temperature T. The decrease of the spin susceptibility with increasing T is confirmed. At sufficient high temperature, the spin susceptibility Chi_s presents an unusual linear temperature dependence Chi_s ~ Chi_s0 -Chi_1 T. Moreover, a linear correlation between Chi_1 and Chi_s0 for increasing hole concentration is displayed. A temperature Tchi, independent of hole doping characterizes this scaling. Comparison with other cuprates of the literature(LSCO, Tl-2201 and Bi-2212), over the same overdoped range, shows similarities with above results. These non conventional metal features will be discussed in terms of a singular narrow-band structure.Comment: 16 pages, 4 figure

    X-ray anomalous scattering investigations on the charge order in α′\alpha^\prime-NaV2_2O5_5

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    Anomalous x-ray diffraction studies show that the charge ordering in α′\alpha^\prime-NaV2_2O5_5 is of zig-zag type in all vanadium ladders. We have found that there are two models of the stacking of layers along \emph{c-}direction, each of them consisting of 2 degenerated patterns, and that the experimental data is well reproduced if the 2 patterns appears simultaneously. We believe that the low temperature structure contains stacking faults separating regions corresponding to the four possible patterns.Comment: Submitted to Phys. Rev. Lett., 4 pages, 4 eps figures inserted in the tex

    Orthorhombic versus monoclinic symmetry of the charge-ordered state of NaV2O5

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    High-resolution X-ray diffraction data show that the low-temperature superstructure of alpha-NaV2O5 has an F-centered orthorhombic 2a x 2b x 4c superlattice. A structure model is proposed, that is characterized by layers with zigzag charge order on all ladders and stacking disorder, such that the averaged structure has space group Fmm2. This model is in accordance with both X-ray scattering and NMR data. Variations in the stacking order and disorder offer an explanation for the recently observed devils staircase of the superlattice period along c.Comment: REVTEX, 4 pages including 2 figures, shortened, submitted to PR

    Nanoscale mechanical control of surface electrical properties of manganite films with magnetic nanoparticles

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    Mechanical control of electrical properties in complex heterostructures, consisting of magnetic FeOx nanoparticles on top of manganite films, is achieved using atomic force microscope AFM based methods. Under applied pressure of the AFM tip, drop of the electrical conductivity is observed inducing an electrically insulating state upon a critical normal load. Current and surface potential maps suggest that the switching process is mainly governed by the flexoelectric field induced at the sample surface. The relaxation process of the electrical surface potential indicates that the diffusion of oxygen vacancies from the bulk of the manganite films towards the sample surface is the dominant relaxation mechanism. The magnetic FeOx nanoparticles, staying attached to the sample surface after the rubbing, protect the underlying manganite films and provide stability of the observed resistive switching effect. The employed mechanical control gives a new freedom in the design of resistive switching devices since it does not depend on the film thickness, and biasing is not neede

    Phenomenology of the normal state in-plane transport properties of high-TcT_c cuprates

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    In this article, I review progress towards an understanding of the normal state (in-plane) transport properties of high-TcT_c cuprates in the light of recent developments in both spectroscopic and transport measurement techniques. Against a backdrop of mounting evidence for anisotropic single-particle lifetimes in cuprate superconductors, new results have emerged that advocate similar momentum dependence in the transport decay rate Γ\Gamma({\bf k}). In addition, enhancement of the energy scale (up to the bare bandwidth) over which spectroscopic information on the quasiparticle response can be obtained has led to the discovery of new, unforeseen features that surprisingly, may have a significant bearing on the transport properties at the dc limit. With these two key developments in mind, I consider here whether all the ingredients necessary for a complete phenomenological description of the anomalous normal state transport properties of high-TcT_c cuprates are now in place.Comment: 31 pages, 10 figure

    Change of the Ground State upon Hole Doping Unveiled by Ni Impurity in High-TcT_{\rm c} Cuprates

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    The electronic ground state in high-TcT_{\rm c} cuprates where the superconducting state is suppressed by Ni substitution has been investigated in La2−x_{2-x}Srx_xCu1−y_{1-y}Niy_yO4_4 from the specific heat and muon spin relaxation measurements. It has been found that the ground state changes from a magnetically ordered state with the strong hole-trapping by Ni to a metallic state with the Kondo effect of Ni with increasing hole-concentration. Moreover, the analysis of the results has revealed that a phase separation into the magnetically ordered phase and the metallic phase occurs around the boundary of two phases.Comment: 11pages, 4 figure
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