Author_Institution :
Dept. of Phys., Southeast Univ., Nanjing, China
Abstract :
In this paper, we report a study on heat-induced magnetic properties changes of Mn3[Fe(CN)6]2·XH2O. Molecular magnet nickel(II) hexacyanoferrate(III) powder Mn3[Fe(CN)6]2·XH2O was prepared by coprecipitation method. The coprecipitated powder was annealed in vacuum at different temperatures of 80, 100, 130, and 150°C. Variation of magnetic properties with different annealed temperatures was studied by elemental analysis, powder X-ray diffraction, Fourier-transform infrared, Mössbauer and magnetization measurements. From the elemental analysis, we can know the powders annealed at the different temperatures have the chemical composition of Mn3[Fe(CN)6]2·XH2O. The compounds at the different temperatures are characterized by two intense peaks, 2070 and 2149 cm-1, which can be assigned to v(FeII-CN-MnIII) and v(FeIII-CN-MnII) respectively. The line broadening and position found in the XRD peaks of the four samples are all but the same. This suggested no microstructural changes after the annealing at the different temperatures. By using Sherrer´s equation: D = kλ/βcosθ, where λ is the X-ray wavelength, β the half-peak width, θ the Bragg angle in degrees, and k the shape factor often assigned a value of 0.89, the average sizes of all the samples were estimated to be about 10 nm. Mössbauer measurements show that the FeII-CN-MnIII bond is formed in the annealed samples.
Keywords :
Fourier transform spectra; Mossbauer effect; X-ray diffraction; annealing; bonds (chemical); crystal microstructure; infrared spectra; magnetic particles; magnetisation; manganese compounds; molecular magnetism; powders; precipitation; spectral line broadening; Bragg angle; FTIR; Fourier-transform infrared spectroscopy; Mn3[Fe(CN)6]2H2O; Mossbauer measurements; Sherrer´s equation; X-ray wavelength; XRD peaks; annealing temperatures; average sizes; bond; chemical composition; coprecipitated powder; coprecipitation method; elemental analysis; half-peak width; heat-induced magnetic property changes; line broadening; magnetization measurements; microstructural changes; molecular magnet nickel(II) hexacyanoferrate(III) powder; powder X-ray diffraction; shape factor; temperature 100 degC; temperature 130 degC; temperature 150 degC; temperature 80 degC; wave number 2070 cm-1; wave number 2149 cm-1; Annealing; Heating;
