Size Effects on the Magnetic Properties of a System of ε-Fe2O3 Nanoparticles Embedded in a SiO2 Xerogel Matrix Full article
| Journal |
Ceramics International
ISSN: 0272-8842 |
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| Output data | Year: 2025, Volume: 51, Number: 1, Pages: 650-663 Pages count : 14 DOI: 10.1016/j.ceramint.2024.11.048 | ||||||
| Tags | Coercive force; Magnetic anisotropy; Magnetic susceptibility; SiO2 nanoparticles; Superparamagnetism; X ray analysis; X ray diffraction analysis | ||||||
| Authors |
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| Affiliations |
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Funding (1)
| 1 | Russian Science Foundation | 24-12-20011 |
Abstract:
A representative series of samples consisting of fine ε-Fe2O3 nanoparticles uniformly distributed over the SiO2 xerogel matrix with an iron oxide content of 5–33 wt % has been synthesized and studied by mutually complementary physical methods. It has been shown by the X-ray diffractometry and high-resolution electron microscopy examination that, with increasing iron oxide concentration, the average particle size <d> increases from 4 to 11 nm. According to the X-ray diffractometry and Mӧssbauer spectroscopy data, the samples with an iron oxide content of 5–20 wt % are single-phase, while at the highest Fe2O3 concentration (33 wt %), the β-Fe2O3 and α-Fe2O3 phases arise. As the average particle size <d> increases, a monotonic increase in coercivity HC and remanent magnetization MR of the synthesized systems at room temperature is observed, which is indicative of their magnetic hysteresis. The magnetic transition known to occur in the ε–Fe2O3 oxide manifests itself in all the investigated samples as a drastic change in the HC and MR values at 150–75 K. At the same time, a thorough analysis of the temperature dependence of the real part of the ac magnetic susceptibility χ′ has shown that the particles with a size smaller than a critical value of dC ∼6.5 nm do not undergo the magnetic transition and have a much lower magnetic anisotropy constant as compared with coarser particles (d > dC). It has been found that, in the low-temperature region, the magnetic moments of these fine particles experience superparamagnetic blocking. It has been established that the size effects that arise in ultra-fine ε–Fe2O3 particles has a serious impact on the macroscopic magnetic properties of the highly dispersed systems based on them.
Cite:
Balaev D.A.
, Knyazev Y.V.
, Semenov S.V.
, Dubrovskiy A.A.
, Lasukov A.I.
, Skorobogatov S.A.
, Smorodina E.D.
, Kirillov V.L.
, Martyanov O.N.
Size Effects on the Magnetic Properties of a System of ε-Fe2O3 Nanoparticles Embedded in a SiO2 Xerogel Matrix
Ceramics International. 2025. V.51. N1. P.650-663. DOI: 10.1016/j.ceramint.2024.11.048 WOS Scopus AN OpenAlex
Size Effects on the Magnetic Properties of a System of ε-Fe2O3 Nanoparticles Embedded in a SiO2 Xerogel Matrix
Ceramics International. 2025. V.51. N1. P.650-663. DOI: 10.1016/j.ceramint.2024.11.048 WOS Scopus AN OpenAlex
Dates:
| Submitted: | Sep 23, 2024 |
| Accepted: | Nov 3, 2024 |
| Published online: | Nov 8, 2024 |
| Published print: | Jan 1, 2025 |
Identifiers:
| Web of science: | WOS:001396052100001 |
| Scopus: | 2-s2.0-85208761923 |
| Chemical Abstracts: | 2024:2476244 |
| OpenAlex: | W4404160879 |