  We measured the magnetoresistance as a function of temperature down to 20mK
and magnetic field for a set of underdoped PrCeCuO (x=0.12) thin films with
controlled oxygen content. This allows us to access the edge of the
superconducting dome on the underdoped side. The sheet resistance increases
with increasing oxygen content whereas the superconducting transition
temperature is steadily decreasing down to zero. Upon applying various magnetic
fields to suppress superconductivity we found that the sheet resistance
increases when the temperature is lowered. It saturates at very low
temperatures. These results, along with the magnetoresistance, cannot be
described in the context of zero temperature two dimensional
superconductor-to-insulator transition nor as a simple Kondo effect due to
scattering off spins in the copper-oxide planes. We conjecture that due to the
proximity to an antiferromagnetic phase magnetic droplets are induced. This
results in negative magnetoresistance and in an upturn in the resistivity.
