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A series of perovskite compounds of La1-x-yCaxKyMnO3 was prepared by hydrothermal disproportionation reaction of MnO2. The three oxidation states of manganese(Mn3+, Mn4+ and Mn5+) can stably exist in the compounds. Under room temperature conditions, twice and three times modulated structure produced by the charge ordering can be observed by X-ray diffraction(XRD), select area electron diffraction(SAED) and high resolution transmission electron microscopy(HR-TEM). The splits of the diffraction peaks of the single crystals confirmed by synchrotron X-ray diffraction experiment are in accordance with those of the powder sample. The existence of the different oxidation states of Mn3+, Mn4+ and Mn5+ can be considered to be the dominating reason of the complicated room temperature modulated structure.
A series of perovskite compounds of La1-x-yCaxKyMnO3 was prepared by hydrothermal disproportionation reaction of MnO2. The three oxidation states of manganese (Mn3 +, Mn4 + and Mn5 +) can stably exist in the compounds. Under room temperature conditions, twice and three times modulated structure produced by the charge ordering can be observed by X-ray diffraction (XRD), select area electron diffraction (SAED) and high resolution transmission electron microscopy (HR-TEM). The splits of the diffraction peaks of the synchrotron X-ray diffraction experiment are in accordance with those of the powder sample. The existence of the different oxidation states of Mn3 +, Mn4 + and Mn5 + can be considered to be the dominating reason of the complicated room temperature modulated structure.