Gil Drachuck, Meni Shay, Galina Bazalitsky, Jorge Berger, Amit Keren
We report direction-dependent susceptibility and resistivity measurements on La$_{2-x}$Sr$_{x}$CuO$_{4}$ single crystals. These crystals have rectangular needle-like shapes with the crystallographic \textquotedblleft c\textquotedblright\ direction parallel or perpendicular to the needle axis, which, in turn, is in the applied field direction. At optimal doping we find finite diamagnetic susceptibility above $T_{\mathbf{c}}$ only when the field is perpendicular to the planes. In an underdoped sample we could find a finite diamagnetic susceptibility above $T_{\mathbf{c}}$\ in both field directions. The variations in the susceptibility data suggest a different origin for the fluctuating superconductivity above $T_{\mathbf{c}}$\ between underdoping (below 10%) and optimal doping.
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http://arxiv.org/abs/1111.0470
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