Thermal history dependent photoconductivity in Pr0.5Sr0.5MnO3 thin film

Abstract

Thermal history dependent photoconductivity has been observed in the thermal hysteresis region of Pr0.5Sr0.5MnO3 thin film. In the cooling process, the film shows an upward resistance relaxation in darkness. Under light illumination, the transient photoconductivity effect is observed. However, it exhibits a downward resistance relaxation without illumination and persistent photoconductivity (PPC) behavior with light illumination in the warming process. The PPC ratio is 18.1% at 110 K with a light density of 1.25 mW mm−2. It is found that the external magnetic field plays a similar role as the light illumination. The persistent magnetoresistance ratio reaches 44.4% at 110 K with a low magnetic field of 0.25 T. The underlying mechanism is discussed based on phase competition and phase stability switch between ferromagnetic metal and charge- and orbital-ordered insulator states. The results may be important for practical applications in photo-/magnetic field sensitive and memory devices.