Steps in the negative-differential-conductivity regime of a superconductor.
Current-voltage characteristics were measured in the mixed state of Y(1)Ba(2)Cu(3)O(7-delta) superconducting films in the regime where flux flow becomes unstable and the differential conductivity dj/dE becomes negative. Under conditions where its negative slope is steep, the j(E) curve develops a pronounced staircase-like pattern. We attribute the steps in j(E) to the formation of a dynamical phase consisting of the successive nucleation of quantized distortions in the local vortex velocity and flux distribution within the moving flux matter.
Kunchur
M N
MN
Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208, USA.
Ivlev
B I
BI
Knight
J M
JM