EXPRESSION FOR THE TIME-DEPENDENCE OF CURRENT-DENSITY WITH AVALANCHE DYNAMICS IN TYPE-II SUPERCONDUCTORS

Based on the concept of self-organized criticality, we have developed an expression for the current decay of type-II superconductors: j=j(c) -j(c)[kT/U0ln(l+betat/tau)]1/beta. This expression can be a general de scription of current decay in a wide range of j. Magnetic-relaxation e xperimental results in both high-T(c) superconductors (single crystals of YBa2Cu30x and Bi2Sr2CaCu2Ox) and conventional type-II superconduct ors (multifilamentary wire of Nb3Sn) have shown excellent agreement wi th our theoretical predication. Several microscopic parameters such as the characteristic energy and the characteristic time for these type- II superconductors have been extracted from the experimental data.