EXAFS analysis of cations distribution in structure of Co 1−x Ni x Fe 2 O 4 nanoparticles obtained by hydrothermal method in aloe vera extract solution
| Autor: | Ekaphan Swatsitang, Santi Maensiri, Unchista Wongpratat |
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| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Materials science Ionic radius Extended X-ray absorption fine structure Analytical chemistry General Physics and Astronomy 02 engineering and technology Surfaces and Interfaces General Chemistry Crystal structure Coercivity 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Surfaces Coatings and Films Lattice constant Ferrimagnetism 0103 physical sciences Particle size 0210 nano-technology Superparamagnetism |
| Zdroj: | Applied Surface Science. 380:60-66 |
| ISSN: | 0169-4332 |
| DOI: | 10.1016/j.apsusc.2016.02.082 |
| Popis: | Effect of cations distribution upon EXAFS analysis on magnetic properties of Co1−xNixFe2O4 (x = 0, 0.25, 0.50, 0.75 and 1.0) nanoparticles prepared by the hydrothermal method in aloe vera extract solution were studied. XRD analysis confirmed a pure phase of cubic spinel ferrite of all samples. Changes in lattice parameter and particle size depended on the Ni content with partial substitution and site distributions of Co2+, Ni2+ ions of different ionic radii at both tetrahedral and octahedral sites in the crystal structure. Particle sizes of samples estimated by TEM images were found to be in the range of 10.87–62.50 nm. The VSM results at room temperature indicated the ferrimagnetic behavior of all samples. Superparamagnetic behavior was observed in NiFe2O4 sample. The coercivity (Hc) and remanance (Mr) values were related to the particle sizes of samples. The saturation magnetization (Ms) was increased by a factor of 1.4 to a value of 57.57 emu/g, whereas the coercivity (Hc) was decreased by a factor of 20 to a value of 63.15 Oe for a sample with x = 0.75. In addition to the cations distribution, the increase of aspect ratio (surface to volume ratio) due to the decrease of particle size could significantly affect the magnetic properties of the materials. |
| Databáze: | OpenAIRE |
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