SUPERCONDUCTING PROPERTIES OF POLYCRYSTALLINE YBA2CU3O7-DELTA - EVIDENCE FOR A GAUGE GLASS

We report measurements of ac susceptibility and I-V characteristics performed on a polycrystalline sintered sample of YBa2Cu3O7-delta near the superconducting transition at selected magnetic fields between 0.1 and 80.9 G. The behavior of chi(ac) provides evidence that this sample is a gauge-glass granular superconductor. I-V measurements performed at H = 0.5, 8.1, and 80.9 G show scaling behavior consistent with a superconducting phase transition and provide evidence that the gauge-glass transition occurs at a well-defined transition temperature T(c).