X-ray-induced persistent photoconductivity in La0.9A0.1MnO3 (A=Sr, Ca)

We observed persistent photoconductivity (PPC) in La-based perovskite manganese oxides, La0.9Sr0.1MnO3 (LSMO) and La0.9Ca0.1MnO3 (LCMO), under X-ray irradiation. The PPC in LSMO was attributed to the collapse of the charge- and orbital-ordered (CO and OO, respectively) states, similar to that reported in previous papers. This PPC effect was different from that observed in a similar compound with a slightly different composition. This difference was explained in terms of doped carriers. This observation of PPC in LCMO is the first result of the PPC in a compound in which the ground state is not the CO phase; it was attributed to the collapse of the OO ground state. We proposed that OO ground state is a prerequisite for the occurrence of PPC in these compounds.