Visualization of the Local Insulator-Metal Transition in Pr 0.7 Ca 0.3 MnO 3

Abstract
The light-induced insulator-metal transition in the “colossal magnetoresistance” compound Pr 0.7 Ca 0.3 MnO 3 is shown to generate a well-localized conducting path while the bulk of the sample remains insulating. The path can be visualized through a change of reflectivity that accompanies the phase transition. Its visibility provides a tool for gaining insight into electronic transport in materials with strong magnetic correlations. For example, a conducting path can be generated or removed at an arbitrary position just because of the presence of another path. Such manipulation may be useful in the construction of optical switches.