Nonbolometric photoresponse in (La,Pr)_(0.67)Ca_(0.33)MnO_3 thin films

摘要

We have studied light-induced resistance changes (photoresponse) in the colossal magnetoresistive manganite material (La,Pr)_(0.67)Ca_(0.33)MnO_3. The metal-insulator transition in this material is understood to be driven by the percolation of the metallic channel in an inhomogeneous matrix of insulating and metallic components. Our experiments reveal a nonthermal (nonbolometric) component of the light-induced resistance change, in addition to the expected resistance change related to heating (bolometric effect). This nonthermal component is seen only in the metal-insulator transition region. Our results suggest that this component may be associated with the light-induced resistance decrease in the insulating regions through an electronic mechanism.