RESISTIVE TRANSITION BROADENING IN 2-PHASE POLYCRYSTALLINE YBACUO

A model proposed by Tinkham1 to explain the resistance versus temperat ure broadening found in high T(c) superconductors in applied magnetic fields is extended to ''foot and knee''-structured data taken on polyc rystalline YBa2Cu3O6+delta. The proposed extension involves a series c ombination of two types of superconductors. For this series combinatio n to result, a critical ratio of the two types of superconductors must be met-a result common to both percolation and randomized cellular au tonoma theory. This critical ratio is investigated via statistical com puter models of a polycrystalline superconductor having two phases of crystallites-one with substantially lower J(c) than the other.