Diamagnetic persistent current in diffusive normal-metal rings.
We have measured a diamagnetic persistent current with flux periodicities of both h/e and h/2e in an array of thirty diffusive mesoscopic gold rings. At the lowest temperatures, the magnitudes of the currents per ring corresponding to the h/e- and h/2e-periodic responses are both comparable to the Thouless energy E(c) identical with Planck's over 2pi/tau(D), where tau(D) is the diffusion time. Taken in conjunction with earlier experiments, our results strongly challenge the conventional theories of persistent current. We consider a new approach associated with the saturation of the phase coherence time tau(phi).
Jariwala
E M
EM
Center for Superconductivity Research, Department of Physics, University of Maryland, College Park 20742, USA.
Mohanty
P
P
Ketchen
M B
MB
Webb
R A
RA