Stability of a photoinduced insulator-metal transition inPr1−xCaxMnO3

A photoinduced insulator-metal transition has been found in crystals of ${\mathrm{Pr}}_{1-x}{\mathrm{Ca}}_x{\mathrm{MnO}}_3$ with various doping levels ($x=0.31\mathrm{}$, 0.35, 0.40, 0.45, and 0.50). The current-voltage relationship and the temperature dependence of the stability of the metallic region indicate that the metallic states of all $x$ are of the same origin, and exclude the Joule heating as the mechanism of sustaining the metallic phase. The driving force for the transition is clearly the collapse of the charge-ordered state by the photocarriers.