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 compound...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.展开更多
基金Supported by the National Natural Science Foundation of China(No.90922034)
文摘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.
