Effects of processing parameters on the morphology, structure, and magnetic properties of Cu1−xFexCr2Se4 nanoparticles synthesized with chemical methods

Cu1−xFexCr2Se4 nanoparticles with x = 0, 0.2, and 0.4 were synthesized via thermal decomposition of metal nitrate or chloride salts and selenium powder using different precursor compositions and processing details. Single crystalline nano-belts or nano-rods coexist in the synthesized powder samples with hexagon-shaped plates in dependence on the precursor composition. The belts gathered into conglomerates forming “hierarchical” particles. Visible magnetic circular dichroism (MCD) of Cu1−xFexCr2Se4 nanoparticles embedded into a transparent matrix was investigated for the first time. The similarity of the MCD spectra of all samples showed the similarity of the nanoparticles electronic structure independent of their morphology. Basing on the MCD spectral maxima characteristics, electron transitions from the ground to the excited states were identified with the help of the conventional band theory and the multi-electron approach

Iron Sulfide Nanoparticles: Preparation, Structure, Magnetic Properties

The series of iron sulfide nanoparticles (NPs) were synthesized with the polyol mediated process which exploits high-boiling polyalcohol solvents at different boiling temperatures (TB) what determined the NPs phase state from Fe3S4 to FeS. The XRD and HRTEM revealed the content of the Fe3S4 cubic phase to reduce linearly with the TB increase, and at TB=320 ◦C the FeS phase became predominant. Non monotonous coercivity dependence on the NPs phase state is revealed and interpreted

Iron Sulfide Nanoparticles: Preparation, Structure, Magnetic Properties

The series of iron sulfide nanoparticles (NPs) were synthesized with the polyol mediated process which exploits high-boiling polyalcohol solvents at different boiling temperatures (TB) what determined the NPs phase state from Fe3S4 to FeS. The XRD and HRTEM revealed the content of the Fe3S4 cubic phase to reduce linearly with the TB increase, and at TB=320 ◦C the FeS phase became predominant. Non monotonous coercivity dependence on the NPs phase state is revealed and interpreted

Effects of processing parameters on the morphology, structure, and magnetic properties of Cu1−xFexCr2Se4 nanoparticles synthesized with chemical methods

Cu1−xFexCr2Se4 nanoparticles with x = 0, 0.2, and 0.4 were synthesized via thermal decomposition of metal nitrate or chloride salts and selenium powder using different precursor compositions and processing details. Single crystalline nano-belts or nano-rods coexist in the synthesized powder samples with hexagon-shaped plates in dependence on the precursor composition. The belts gathered into conglomerates forming “hierarchical” particles. Visible magnetic circular dichroism (MCD) of Cu1−xFexCr2Se4 nanoparticles embedded into a transparent matrix was investigated for the first time. The similarity of the MCD spectra of all samples showed the similarity of the nanoparticles electronic structure independent of their morphology. Basing on the MCD spectral maxima characteristics, electron transitions from the ground to the excited states were identified with the help of the conventional band theory and the multi-electron approach

Size dependent magnetic and magneto-optical properties of Ni0.2Zn0.8Fe2O4 nanoparticles

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Size dependent magnetic and magneto-optical properties of Ni0.2Zn0.8Fe2O4 nanoparticles

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала

Structural and magnetic properties of Fe1−x Co x Se1.09 nanoparticles obtained by thermal decomposition

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.A series of Fe1−x CoxSe1.09 (x = 0 to 1) nanoparticles were synthesized by thermal decomposition method. Particles in composition range Fe0.5Co0.5Se1.09 to CoSe1.09 crystallized in monoclinic structure of Co6.8Se8, while FeSe1.09 crystallized in hexagonal structure of FeSe achavalite. Magnetization dependences on temperature and external magnetic field reveal complicated magnetic behavior and correspond to the sum of paramagnetic and superparamagnetic response. Mössbauer spectra contain several paramagnetic doublets with parameters corresponding to nonequivalent positions of divalent and trivalent iron cations with low spin. The nonequivalent positions appeared due to inhomogeneous distribution of Co ions or metal vacancies in iron surrounding

Associating Physical and Chemical Properties to Evaluate Buffer Materials by Th and U Sorption

The physical and chemical properties of buffer materials to be used for a radwaste disposal repository should be evaluated prior to use. In a conventional approach, independent studies of physical and/or chemical characteristics are conducted. This study investigated the relationship between the plastic index (PI) and distribution ratio (Rd) of buffer materials composed of varying ratios of quartz sand and bentonite. Thorium (Th) and Uranium (U) were the nuclides of interest, and both synthetic groundwater and seawater were used as the liquid phases to simulate conditions representative of deep geological disposal within an island. Atterberg tests were used to determine PI values, and batch sorption experiments were employed to measure Rd values. The results show that Th reached maximum sorption behavior when the bentonite content exceeded 30 % of the mixture. Contrariwise, the sorption of U increased linearly with bentonite content, up to bentonite contents of 100%, and this correlation was present regardless of the liquid phase used. A further result is that U has a better additivity with respect to Rd than Th in both synthetic groundwater and synthetic seawater. These results will allow a determination of more effective buffer material composition, and improved estimates of the overall Rd of the buffer material mixture from the Rd of each mineral component