  The transport properties of superconducting single crystal Pb nanowires of 55
nm and 70 nm diameter are studied by standard four electrodes method.
Resistance-temperature (R-T) scans and magneto-resistance (R-H) measurements
show a series of resistance steps with increasing temperature and magnetic
field as the wires are brought toward the normal state. The resistance-current
(R-I) scans at different temperature and magnetic field show that the increase
in R with I is punctuated with sharp steps at specific current values. We
interpret these steps as consequence of phase slip centers (PSCs) in the
superconducting wires enhanced by the presence of the normal Pt electrodes.
