Oxygen-plasma effects have been investigated for La0.7Ca0.3MnO3-delta thin film samples. As a result, an increase in the metal-insulator transition temperature was observed in a thin film sample. On the other hand, an increase in the resistivity as well as a decrease the metal-insulator transition temperature was observed in a sample showing considerable structural disorder. (C) 2004 Elsevier Ltd. All fights reserved.