Flux-flow instability and heating effects in Bi2Sr2CaCu2O8 and YBa2Cu3O7 thin films

We investigated current-voltage curves of Bi2Sr2CaCu2O8 and YBa2Cu3O7 thin films. Voltage jumps due to flux-flow instabilities at high vortex-velociti es were found and interpreted in the framework of the theory of Larkin and Ovchinnikov. The extensions introduced by Bezuglyj et al. account for quasi particle heating during the measurement. While in Bi2Sr2CaCu2O8 the instabi lity is found in the vortex-liquid phase, in YBa2Cu3O7 we observed it in th e vortex-glass phase. Moreover, we studied the temporal behavior of the ins tability in current-voltage curves with a time resolution in the microsecon d range. (C) 2000 Elsevier Science B.V. Ail rights reserved.