St. Stoddart et al., THE PINNING POTENTIAL AT SINGLE FLUX VORTICES INVESTIGATED USING SUBMICRON HALL PROBES, Physica. B, Condensed matter, 194, 1994, pp. 1899-1900
We have imaged individual flux vortices in 200 nm-thick superconductin
g Pb films using sub-micron Hall probes with an excellent combination
of spatial and temporal resolution. Correlation of signals at separate
Hall contacts shows that flux enters the film in correlated bundles o
f approximately 5 mum diameter. With an applied supercurrent, we have
been able to move individual vortices distances of typically 30-40 nm
between minima in the pinning potential that differ by approximately 0
.5eV. We have determined pinning forces as a function of temperature f
or individual pinning sites. At higher applied fields the intervortex
interaction alone is sufficient to move vortices between different pot
ential minima as the temperature approaches T(c).