Papers by Author: G. Chen

Abstract: LiMnO2 are synthesized by hydrothermal technique by using Mn(CH3COO)2.4H2O and MnO2 with the same mole ratio which are dissolved in aqueous solution with different concentration LiOH. Structural characterization based on X-ray diffraction and Raman spectroscopy reveals that LiMnO2 is in a well-order orthorhombic structure with lower stacking faults compared to the LiMnO2 prepared by other techniques. Experimental results show that the concentration of lithium hydroxide in aqueous solution affect the quality of LiMnO2.

Abstract: The complex oxide Eu2Mn2/3Nb4/3O7 structurally characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results of XRD structure analysis shown that the X-ray diffraction profile calculated with monoclinic C2/c model is in a good agreement with the observed X-ray diffraction patterns. In addition to fundamental reflection peaks, super lattice lines could be also assigned with C2/c symmetry. Therefore, it is derived that Eu2Mn2/3Nb4/3O7 phase has not a pyrochlore structure but has a zirconolite-type structure (pyrochlore-related structure) with a C2/c space group. Eu2Mn2/3Nb4/3O7 has two kinds of distorted MO6 octahedra and HTB layers, which deviates from the regular forms. The microstructure of Eu2Mn2/3Nb4/3O7 investigated by TEM also proved the results of XRD structural analysis. It was viewed that HRTEM image of a characteristic twin structure in Eu2Mn2/3Nb4/3O7 which a zirconolite-type structure has.