Structural and magnetic properties of the nanocomposite materials based on a mesoporous silicon dioxide matrix
| Autor: | M. Kraje, N. A. Grigor’eva, Kirill S. Napolskii, Alexey V. Lukashin, A. A. Eliseev, S. V. Grigor’ev, Helmut Eckerlebe |
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| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Materials science Transition temperature Analytical chemistry Iron oxide General Physics and Astronomy Nanoparticle Nanotechnology 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Ferromagnetic resonance law.invention chemistry.chemical_compound chemistry Transmission electron microscopy law 0103 physical sciences 0210 nano-technology Mesoporous material Electron paramagnetic resonance Saturation (magnetic) |
| Zdroj: | Journal of Experimental and Theoretical Physics. 124:476-492 |
| ISSN: | 1090-6509 1063-7761 |
| DOI: | 10.1134/s106377611702011x |
| Popis: | The structural and magnetic properties of the mesoporous systems based on silicon dioxide with a regular hexagonal arrangement of pores several microns in length and several nanometers in diameter, which are filled with iron compound nanofilaments in various chemical states, are studied in detail. The studies are performed using the following mutually complementary methods: transmission electron microscopy, SQUID magnetometry, electron spin resonance, Mossbauer spectroscopy, polarized neutron small-angle diffraction, and synchrotron radiation diffraction. It is shown that the iron nanoparticles in pores are mainly in the γ phase of Fe2O3 with a small addition of the α phase and atomic iron clusters. The effective magnetic field acting on a nanofilament from other nanofilaments is 11 mT and has a dipole nature, the ferromagnetic–paramagnetic transition temperature is in the range 76–94 K depending on the annealing temperature of the samples, and the temperature that corresponds to the change in the magnetic state of the iron oxide nanofilaments is T ≈ 50–60 K at H = 0 and T ≈ 80 K at H = 300 mT. It is also shown that the magnetization reversal of an array of nanofilaments is caused by the magnetostatic interaction between nanofilaments at the fields that are lower than the saturation field. |
| Databáze: | OpenAIRE |
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