Study of dynamical phase of Bi2Sr2CaCu2Oy by local noise measurement

Local fluctuation of vortex density under finite driven current was investi gated in Bi2Sr2CaCu2Oy at various regions in the H-T-J plane. We investigat ed the autocorrelation of the density noise at various places in the sample , as well as the crosscorrelation between them. Results were compared with the phase diagram obtained by numerical simulations. Our experimental resul ts suggest a gradual transition from plastic flow to uniform flow, via inco herent flow with increasing driving current and magnetic field, and the exp erimentally obtained "phase diagram" is in very good agreement with predict ion of the numerical simulation. (C) 2000 Elsevier Science B.V. All rights reserved.