Photoinduced phase transition in Pr0.7Ca0.3MnO3 thin films probed via ultrafast switching characteristics of terahertz radiation

Picosecond electrical transients have been identified as switching characteristics of terahertz radiation from voltage-biased Pr0.7Ca0.3MnO3 thin films excited by femtosecond laser pulses. Despite the fact that the total time-averaged photocurrent exhibits a hysteresis in response to the application of the bias electric field E-bias, we find the considerable attenuation of terahertz radiation. Not the removal of E-bias but rather the sweep of temperature is confirmed to be indispensable for the recovery of terahertz radiation. Our findings can be attributed to the clear manifestation of the intrinsic and persistent photoinduced phase transition in Pr0.7Ca0.3MnO3, the instability of which by a removal of E-bias can be explained by the reconstruction of metallic patches within the charge-ordered insulating phase.