Phase separation and percolation in doped manganites

Currently, phase separation is still a hot topic in the study of colossal magnetoresistive materials. Percolation is widely used to explain its temperature dependent resistivity. In this paper, the percolative process has been observed for the first time using a low temperature magnetic force microscope in La0.33Pr0.34Ca0.33MnO3 thin films. It is found that upon cooling the abrupt decrease in the resistivity is related to the formation of percolation of the ferromagnetic metallic phase in the insulating matrix, while the rapid increase in the resistivity during the warming process is due to the decrease in the magnetization. The microscopic magnetic hysteresis is consistent with the macroscopic resistivity hysteresis. Further work is needed to explain quantitatively the colossal magnetoresistance effect in the doped manganites.