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The coprecipitated powder Co0.75Ni0.75[Fe(CN)6]oXH2O was annealed in vacuum at different temperatures of 80, 130, and 150℃. The effects of heating on its charge transfer properties were studied by elemental analysis, X-ray diffraction (XRD), M?ssbauer spectra, and magnetization measurements. The results of XRD measurements show that no structural changes are involved in the studied samples. According to the result of M?ssbauer spectra, the heating of Co0.75Ni0.75[Fe(CN)6]oXH2O above 80℃ induces an inner charge transfer from CoII or NiII towards FeIII to form the mixed valence system ferri-ferro-cyanide. The magnetic contribution mainly results from FeIII-CN-CoII/NiII because the microstructure FeII-CN-CoIII/NiIII carries no net spin. So differences in magnetic properties may be attributed to heat-induced an inner charge transfer from CoII or NiII towards FeIII. |
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Keywords:Prussian blue analogues; co-precipitation; magnetic properties; M?ssbauer spectra |
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