Electrical Transport Measurements on Polycrystalline Superconducting Y-Ba-Cu-O Films
The current-voltage, I–V, characteristics of polycrystalline Y-Ba-Cu-O films have been measured as a function of temperature. The I–V characteristics are interpreted using a model based upon an array of weak links with a statistical distribution of critical currents. In addition, we find evidence that the supercurrents flow in nearly independent filaments near Tc. Various criteria are discussed with respect to the definition of the transport critical current, Ic, in these films. A temperature dependence for Ic has also been deduced from the I–V data by appealing to an empirical scaling law. We propose that this temperature dependence, Ic α (1-T/Tc)2.2, is representative of the weaker links within the critical current distribution.
KeywordsCritical Current Weak Link Resistive Transition Voltage Criterion OFHC Copper
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- 2.J. W. Ekin, T. M. Larson, A. M. Hermann, Z. Z. Sheng, K. Togano, and H. Kumakura, Double-Step Behavior of Critical Current vs. Magnetic Field in Y-, Bi-, and Tl- Based Bulk High-Tc Superconductors, (preprint submitted to Physica C).Google Scholar