| 1. |
- Baykal, A., et al.
(author)
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Synthesis and Characterization of Dendrimer-Encapsulated Iron and Iron-Oxide Nanoparticles
- 2012
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In: JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM. - : Springer Science and Business Media LLC. - 1557-1939 .- 1557-1947. ; 25:5, s. 1541-1549
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Journal article (peer-reviewed)abstract
- In this paper, a series of iron (Fe) containing nanoparticles were prepared by employing PAMAM (Poly(amidoamine), dendrimers with different generations (G0-G3) as templates and sodium borohydride as a reducing agent. The products have been characterized by TEM, FT-IR, XRD, VSM, TGA, and XPS. XRD analysis reveal low crystallinity of formed particles within the dendrimers, however, crystallinity of the nanoparticles was observed to increase with increasing generation of dendrimers. Dominant phases were determined as magnetite (Fe3O4 or maghemite, gamma-Fe2O3). XPS analysis revealed the chemical composition of nanoparticles as iron oxide which indicated the oxidation of Fe species subsequent to the reduction process, in agreement with XRD analysis. The magnetization curves have superparamagnetic nonhysteretic characteristic at lower fields and with nonsaturation characteristic at high fields. Magnetic evaluation of samples with the 20:1 molar ratio of Fe:PAMAM showed decreasing superparamagnetic character and decreasing saturation magnetisation with increasing generation of dendrimers.
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| 3. |
- Kavas, H., et al.
(author)
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ZnxCu(1-x)Fe2O4 Nanoferrites by Sol-Gel Auto Combustion Route : Cation Distribution and Microwave Absorption Properties
- 2014
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In: Journal of Inorganic and Organometallic Polymers and Materials. - : Springer Science and Business Media LLC. - 1574-1443 .- 1574-1451. ; 24:6, s. 963-970
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Journal article (peer-reviewed)abstract
- The effect of Zn doping on magnetic properties and site preference of cations of CuFe2O4 has been investigated. Zn substituted Cu ferrite nanoparticles with general formula ZnxCu(1-x)Fe2O4 were synthesized by a sol-gel auto combustion method. Samples showed fine particle size with very strong aggregation, due to the high temperatures attained during the combustion process. All samples showed high phase purity assessed from X-ray diffraction analysis and do not have magnetization hysteresis, which reveals superparamagnetic character of the fabricated particles. It was found that a certain amount of Zn substitution in Cu ferrite (0.4 < x < 0.6) causes different site occupation of cations. XRD and magnetic hysteresis data of all samples were analyzed and the cation distribution in spinel ferrites was calculated by these two experimental techniques. It was found that the Neel antiferromagnetic aligned sublattice model is valid below this region (x < 0.4), and above it (x > 0.6) the canted spins at octahedral site are dominant according to the tetrahedral site spins.
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