Yuriy V. Knyazev , Viktor L. Kirillov , Aleksandr A. Krasikov , Stanislav A. Skorobogatov , Dmitry A. Velikanov , Mikhail N. Volochaev , Ekaterina D. Smorodina , Oleg A. Bayukov , Oleg N. Martyanov , Dmitry A. Balaev
{"title":"Embedded ferrihydrite nanoparticles in a SiO2 medium with enhanced superparamagnetic blocking temperature","authors":"Yuriy V. Knyazev , Viktor L. Kirillov , Aleksandr A. Krasikov , Stanislav A. Skorobogatov , Dmitry A. Velikanov , Mikhail N. Volochaev , Ekaterina D. Smorodina , Oleg A. Bayukov , Oleg N. Martyanov , Dmitry A. Balaev","doi":"10.1016/j.ceramint.2024.11.473","DOIUrl":null,"url":null,"abstract":"<div><div>The composite material based on the ferrihydrite nanoparticles (5Fe<sub>2</sub>O<sub>3</sub> · 9H<sub>2</sub>O) encapsulated in SiO<sub>2</sub> matrix was synthesized. Synthesized sample has been characterized by transmission electron microscopy, room-temperature <sup>57</sup>Fe Mössbauer spectroscopyand X-ray photoelectron spectroscopy. The data obtained have shown (i) the presence of isolated ferrihydrite nanoparticles with an average size of ∼4.3 nm in the SiO<sub>2</sub> matrix and (ii) the complete absence of the nanoparticles binding with the SiO<sub>2</sub> matrix. The temperature dependences of the <em>ac</em> and <em>dc</em> magnetization, as well as the temperature evolution of the Mössbauer spectra point out only the occurrence of the superparamagnetic blocking with decreasing temperature. The analysis of the relaxation time of particle magnetic moments have shown no magnetic interactions in the investigated system. A detailed examination of the magnetization curves has revealed that the non-interacted ferrihydrite nanoparticles formed by two magnetic subsystems: paramagnetic surface spins and the magnetically ordered core. Such magnetic morphology results in the significantly decrease of the anisotropy constant (<em>K</em> = 18 ∙ 10<sup>5</sup> erg/cm<sup>3</sup>) compared to interacted nanoparticles. At the same time, a decisive role in the magnetic behavior of the material is played by the subsystem of free spins, which involves about half of all iron atoms on the particle surface.</div></div>","PeriodicalId":267,"journal":{"name":"Ceramics International","volume":"51 4","pages":"Pages 5020-5030"},"PeriodicalIF":5.1000,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Ceramics International","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0272884224055937","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATERIALS SCIENCE, CERAMICS","Score":null,"Total":0}
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Abstract
The composite material based on the ferrihydrite nanoparticles (5Fe2O3 · 9H2O) encapsulated in SiO2 matrix was synthesized. Synthesized sample has been characterized by transmission electron microscopy, room-temperature 57Fe Mössbauer spectroscopyand X-ray photoelectron spectroscopy. The data obtained have shown (i) the presence of isolated ferrihydrite nanoparticles with an average size of ∼4.3 nm in the SiO2 matrix and (ii) the complete absence of the nanoparticles binding with the SiO2 matrix. The temperature dependences of the ac and dc magnetization, as well as the temperature evolution of the Mössbauer spectra point out only the occurrence of the superparamagnetic blocking with decreasing temperature. The analysis of the relaxation time of particle magnetic moments have shown no magnetic interactions in the investigated system. A detailed examination of the magnetization curves has revealed that the non-interacted ferrihydrite nanoparticles formed by two magnetic subsystems: paramagnetic surface spins and the magnetically ordered core. Such magnetic morphology results in the significantly decrease of the anisotropy constant (K = 18 ∙ 105 erg/cm3) compared to interacted nanoparticles. At the same time, a decisive role in the magnetic behavior of the material is played by the subsystem of free spins, which involves about half of all iron atoms on the particle surface.
期刊介绍：
Ceramics International covers the science of advanced ceramic materials. The journal encourages contributions that demonstrate how an understanding of the basic chemical and physical phenomena may direct materials design and stimulate ideas for new or improved processing techniques, in order to obtain materials with desired structural features and properties.
Ceramics International covers oxide and non-oxide ceramics, functional glasses, glass ceramics, amorphous inorganic non-metallic materials (and their combinations with metal and organic materials), in the form of particulates, dense or porous bodies, thin/thick films and laminated, graded and composite structures. Process related topics such as ceramic-ceramic joints or joining ceramics with dissimilar materials, as well as surface finishing and conditioning are also covered. Besides traditional processing techniques, manufacturing routes of interest include innovative procedures benefiting from externally applied stresses, electromagnetic fields and energetic beams, as well as top-down and self-assembly nanotechnology approaches. In addition, the journal welcomes submissions on bio-inspired and bio-enabled materials designs, experimentally validated multi scale modelling and simulation for materials design, and the use of the most advanced chemical and physical characterization techniques of structure, properties and behaviour.
Technologically relevant low-dimensional systems are a particular focus of Ceramics International. These include 0, 1 and 2-D nanomaterials (also covering CNTs, graphene and related materials, and diamond-like carbons), their nanocomposites, as well as nano-hybrids and hierarchical multifunctional nanostructures that might integrate molecular, biological and electronic components.
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