Thermodynamic fluctuations in the superconductor Y1Ba2Cu3O9-: Evidence for three-dimensional superconductivity

The rounding of resistivity near and above the superconductivity transition temperature Tc, observed in the Y1Ba2Cu3O9- superconductor, is found to be a manifestation of thermodynamic fluctuations. A quantitative agreement between the experiment and the three-dimensional (3D) Aslamazov-Larkin theory was achieved near Tc Low-field measurements of the excess diamagnetism are also in agreement with the 3D theory of Prange. These results strongly suggest that superconductivity in high-Tc copper oxides (Y1Ba2Cu3O9-) is basically 3D in nature. © 1987 The American Physical Society.