CHARACTERISTIC FEATURES OF VORTEX DEPINNING IN A LAYERED SUPERCONDUCTOR

The field H(T) for the onset of dissipation is estimated self-consist ently from the results of an investigation of the transverse resistanc e and current-voltage characteristics of a Bi2Sr2CaCu2O8 (BSCCO-2212) single crystal in a mixed state, It is established that H is close to H-c1 in the interval T-c/2 less than or equal to T less than or equal to T-c. Rapid growth of H(T), accompanied by a transformation of the current-voltage characteristics, as the temperature decreases below a pproximate to 40 K attests to the formation of a nonvanishing region o f stability of an ordered state of the vortex system, possibly as a re sult of a change in the effective dimensionality of the fluxoid. (C) 1 997 American Institute of Physics.