Synthesis of various morphological Ca 0.75 Er 0.25 MnO 3 powders by hydrothermal method and their electrical properties

The Ca0.75Er0.25MnO3 powders with better conductive properties and various morphologies have been prepared by using hydrothermal method with different concentrations of KOH and polyethylene glycol 400 (PEG-400). The resistivity of Ca0.75Er0.25MnO3 powders was decreased gradually with increase in KOH concentration. When it was 1000 g L−1, the resistivity obtained the smallest value and in this case, the electrical conduction mechanism was followed thermal activation conduction mechanism. Furthermore, the effect of PEG-400 concentration on the morphology and the mechanism for forming different morphologies were elaborated. When PEG-400 concentration was 1 g L−1, the particles were presented cube structure. And when it was 2 g L−1, the particles were presented rod structure. While the concentration was more than 2 g L−1, the powders were all presented planchet structure, but the particles were enlarged with increase in PEG-400. The resistivity of the powders with the rod structure reached the smallest value of 0.2705 kΩ m, because the rod structure is conducive to the formation of the conductivity pathway.