Persistent and transient photoconductivity in oxygen-deficientLa2/3Sr1/3MnO3−δthin films

Abstract

Light illumination produces major, interesting changes of the electrical properties of oxygen deficient ${\mathrm{La}}_{2/3}{\mathrm{Sr}}_{1/3}{\mathrm{MnO}}_{3\ensuremath{-}\ensuremath{\delta}}$ thin films. At small oxygen deficiency, the classical insulator-metal $(I\ensuremath{-}M)$ transition at a temperature ${T}_{p}$ decreases with increasing oxygen deficiency. The low-temperature metallic behavior in darkness shows a persistent increase of the conductivity with light. This photoconductivity increases with oxygen deficiency (from a few to $60%).$ At large oxygen deficiency, the films are semiconducting in darkness, from helium to room temperature and light induces a transient photoconductivity and a low-temperature $I\ensuremath{-}M$ transition. The intriguing possibility of collective light induced magnetism is discussed.