Direct observation of current-induced conductive path in colossal-electroresistance manganite thin films

Manganites are known to often show colossal electroresistance (CER) in addition to colossal magnetoresistance. The (La1-yPry)1-xCaxMnO3 (LPCMO) system has a peculiar CER behavior in that little change of magnetization occurs. We use a magnetic force microscope to uncover the CER mechanism in the LPCMO system. In contrast to the previous belief that current reshapes the ferromagnetic metallic (FMM) domains, we show that the shape of the FMM domains remain virtually unchanged after passing electric current. Instead, it is the appearance of a tiny fraction of FMM "bridges" that is responsible for the CER behavior.