Nonbolometric photoresponse in (La,Pr)0.67Ca0.33MnO3 thin films

Abstract

We have studied light-induced resistance changes (photoresponse) in the colossal magnetoresistive manganite material (La,Pr)0.67Ca0.33MnO3. 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.

Modulation of persistent photoconductivity by electric-field-controlled strain in thin films of La0.39Pr0.24Ca0.37MnO3

“…As the temperature coefficient (dR/dT) below T MI /T IM is positive, the heating effect caused by laser will increase the resistance and the resistance will drop after the light is switched off. 15,21 The observed PPC effect is independent of the polarity and magnitude of bias current [see Fig. 4(b)].…”

“…The studies on photo-induced effects are quite active but not as extensive as those on CMR effects. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] The origin of these effects has not been well-understood yet. Miyano et al demonstrated a photo-induced transition from chargeordered state to metallic state in an electric-field biased Pr 0.7 Ca 0.3 MnO 3 single crystal.…”