411 research outputs found

    Helicoidal surfaces with constant anisotropic mean curvature

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    We study surfaces with constant anisotropic mean curvature which are invariant under a helicoidal motion. For functionals with axially symmetric Wulff shapes, we generalize the recently developed twizzler representation of Perdomo to the anisotropic case and show how all helicoidal constant anisotropic mean curvature surfaces can be obtained by quadratures

    Evidence of unconventional low-frequency dynamics in the normal phase of Ba(Fe1-xRhx)2As2 iron-based supercondutors

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    This work presents 75As NMR spin echo decay rate (1/T2) measurements in Ba(Fe1-xRhx)2As2 superconductors, for 0.041 < x < 0.094. It is shown that 1/T2 increases upon cooling, in the normal phase, suggesting the onset of an unconventional very low-frequency activated dynamic. The correlation times of the fluctuations and their energy barriers are derived. The motion is favored at large Rh content, while it is hindered by the application of a magnetic field perpendicular to the FeAs layers. The same dynamic is observed in the spin-lattice relaxation rate, in a quantitatively consistent manner. These results are discussed in the light of nematic fluctuations involving domain wall motion. The analogies with the behaviour observed in the cuprates are also outlined

    77^{77}Se and 63^{63}Cu NMR studies of the electronic correlations in Cux_xTiSe2_2 (x=0.05,0.07x=0.05, 0.07)

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    We report 77^{77}Se and 63^{63}Cu nuclear magnetic resonance (NMR) investigation on the charge-density-wave (CDW) superconductor Cux_xTiSe2_2 (x=0.05x=0.05 and 0.07). At high magnetic fields where superconductivity is suppressed, the temperature dependence of 77^{77}Se and 63^{63}Cu spin-lattice relaxation rates 1/T_{1}followalinearrelation.Theslopeof follow a linear relation. The slope of ^{77}1/T_{1}$ vs \emph{T} increases with the Cu doping. This can be described by a modified Korringa relation which suggests the significance of electronic correlations and the Se 4\emph{p}- and Ti 3\emph{d}-band contribution to the density of states at the Fermi level in the studied compounds.Comment: Revised manuscript. Submitted to Journal of Physics: Condensed Matte
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