Strain and Curent Induced Multiphase Coexistence in (La$_{0.5}$Pr$_{0.5}$)$_{0.67}$Ca$_{0.33}$MnO$_{3}$ Probed by Magnetic Force Microscopy*

The ferromagnetic (FM) domain structure of a thin film (La$_{0.5}$Pr$_{0.5})_{0.67}$Ca$_{0.33}$MnO$_{3}$ sample grown on a (110) NdGaO$_{3}$ (NGO) substrate was investigated using low-temperature magnetic force microscopy with temperature control, an external magnetic field and an electric field across the sample. We observed that the FM domains form stable patterns with in-plane magnetization at 78K. At higher temperatures the system enters a fluid phase separated (FPS) state. The FM domains change as the voltage across the sample increases. We believe that competition between a charge-ordered insulating (COI) phase and a ferromagnetic metallic (FMM) phase exists in this FPS state and the COI phase may be driven to an FMM phase by an electric field.