Parallel and perpendicular susceptibility above T-c in La2-xSrxCuO4 single crystals

Article

关键词: LOCK-IN;    TRANSITION;    BI2SR2CACU2O8+DELTA;    SUPERCONDUCTOR;    DIAMAGNETISM;    STATE;   

DOI  :  10.1103/PhysRevB.85.184518

来源: SCIE

【 摘 要 】

We report direction-dependent susceptibility and resistivity measurements on La2-xSrxCuO4 single crystals. These crystals have rectangular needle-like shapes with the crystallographic c 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-c, namely fluctuating superconductivity (FSC), only when the field is perpendicular to the planes. In underdoped samples we find FSC in both field directions. We provide a phase diagram showing the FSC region, although it is sample dependent in the underdoped cases. The variations in the susceptibility data suggest a different origin for the FSC between underdoping (below 10%) and optimal doping. Finally, our data indicate that the spontaneous vortex diffusion constant above T-c is anomalously high.

【 授权许可】

Free