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Magnetic collective state formation upon tuning the interparticle interactions in ensembles of ultrafine ferrihydrite nanoparticles / D. A. Balaev, A. A. Krasikov, Yu. V. Knyazev [et al.] // Nano-Struct. Nano-Objects. - 2024. - Vol. 37. - Ст. 101089, DOI 10.1016/j.nanoso.2023.101089. - Cited References: 93. - The authors thank M.N. Volochaev for the TEM investigations . - ISSN 2352-507X. - ISSN 2352-5088
Кл.слова (ненормированные):
Nanoparticle coating -- Superspin-glass state -- Superparamagnetic blocking -- Surface spin subsystem
Аннотация: The results of a study of the dynamic (alternating current magnetic susceptibility) and static magnetic properties, as well as 57Fe Mössbauer spectrometry and ferromagnetic resonance of two-line ferrihydrite nanoparticle systems with varying intensities of magnetic interparticle interactions are reported. The strength of the magnetic interparticle interactions has been tuned by coating (with various degrees of coating) the ferrihydrite particles (2–4 nm in size and an average size ∼2.7 nm) of the initial synthetic sample by arabinogalactan. Also, a biogenic ferrihydrite sample (an average particle size of 2-nm) with a natural organic coating was studied and it has the weakest magnetic interparticle interactions among of all the samples. Relaxation times of the particle’s magnetic moment were determined by the data of static and dynamic magnetic susceptibilities and from analysis of 57Fe Mössbauer spectrometry. Based on the temperature dependences of the relaxation times, it has been concluded that the predominantly collective processes of freezing of the particle magnetic moments occur under the action of the magnetic interparticle interactions. It is shown that an important role in these processes is played by a magnetic subsystem of the surface spins of the particles. The effect of the interplay between the surface spin and magnetic moment subsystems on the static magnetic properties (low-temperature magnetic hysteresis loops) and the parameters of the microwave absorption line under the magnetic resonance conditions is discussed.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk 660036, Russia
Federal Research Center KSC SB RAS, Krasnoyarsk 660036, Russia
Institute of Chemistry and Chemical Technology, Federal Research Center KSC SB RAS, Krasnoyarsk 660036, Russia

Доп.точки доступа:
Balaev, D. A.; Балаев, Дмитрий Александрович; Krasikov, A. A.; Красиков, Александр Александрович; Knyazev, Yu. V.; Князев, Юрий Владимирович; Yaroslavtsev, R. N.; Ярославцев, Роман Николаевич; Velikanov, D. A.; Великанов, Дмитрий Анатольевич; Mikhlin, Yu. L.; Volochaev, M. N.; Волочаев, Михаил Николаевич; Bayukov, O. A.; Баюков, Олег Артемьевич; Ladygina, V. P.; Stolyar, S. V.; Столяр, Сергей Викторович; Iskhakov, R. S.; Исхаков, Рауф Садыкович
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Separating the contributions of the magnetic subsystems in antiferromagnetic ferrihydrite nanoparticles by analyzing the magnetization in fields of up to 250 kOe / A. A. Krasikov, D. A. Balaev, A. D. Balaev [et al.] // J. Magn. Magn. Mater. - 2024. - Vol. 592. - Ст. 171781, DOI 10.1016/j.jmmm.2024.171781. - Cited References: 84. - This study was supported by his work was supported by the Russian Science Foundation, project no. 22–72-00134. - Authors thank to D.A. Velikanov, S.V. Komogortsev for fruitful discussions . - ISSN 0304-8853. - ISSN 1873-4766
Аннотация: Contributions of different magnetic subsystems formed in the systems of synthetic ferrihydrite nanoparticles (characterized previously) with an average size of ˂d˃ ≈ 2.7 nm coated with polysaccharide arabinogalactan in different degrees have been separated by measuring the dependences of their magnetization M on magnetic field H of up to 250 kOe on vibrating sample and pulsed magnetometers. The use of a wide measuring magnetic field range has been dictated by the ambiguity in identifying a linear M(H) portion for such antiferromagnetic nanoparticle systems within the conventional field range of 60–90 kOe. The thorough analysis of the magnetization curves in the temperature range of 100–250 K has allowed the verification of the contributions of (i) uncompensated magnetic moments µun in the superparamagnetic subsystem, (ii) the subsystem of surface spins with the paramagnetic behavior, and (iii) the antiferromagnetic susceptibility of the antiferromagnetically ordered ferrihydrite particle core. As a result, a model of the magnetic state of ferrihydrite nanoparticles has been proposed and the numbers of spins corresponding to magnetic subsystems (i)–(iii) have been estimated. An average magnetic moment μun of ∼ 145 μB (μB is the Bohr magneton) per particle corresponds approximately to 30 decompensated spins of iron atoms in a particle (about 3 % of all iron atoms), which, according to the Néel’s hypothesis μun ∼ ˂d˃3/2, are localized both on the surface and in the bulk of an antiferromagnetically ordered particle. The fraction of free (paramagnetic) spins is minimal in the sample without arabinogalactan coating of the nanoparticle surface (7 %) and is attained 20 % of all iron atoms in the sample with the highest degree of spatial separation of particles. According to this estimation, paramagnetic spins are located mainly on the edges and protruding areas of particles. Most magnetic moments of iron atoms are ordered antiferromagnetically and the corresponding magnetic susceptibility of this subsystem behaves as in an antiferromagnet with the randomly distributed crystallographic axes, i.e., increases with temperature.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center of Siberian Branch of Russian Academy of Sciences, Krasnoyarsk, Russia
Federal Research Center of Siberian Branch of Russian Academy of Sciences Krasnoyarsk, Russia

Доп.точки доступа:
Krasikov, A. A.; Красиков, Александр Александрович; Balaev, D. A.; Балаев, Дмитрий Александрович; Balaev, A. D.; Балаев, Александр Дмитриевич; Stolyar, S. V.; Столяр, Сергей Викторович; Yaroslavtsev, R. N.; Ярославцев, Роман Николаевич; Iskhakov, R. S.; Исхаков, Рауф Садыкович
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Studying the ferromagnetic resonance heating of an isotropic superparamagnet by the example of biogenic ferrihydrite nanoparticles / S. V. Stolyar, O. A. Li, A. M. Vorotynov [et al.] // Bull. Russ. Acad. Sci.: Phys. - 2024. - Vol. 88, Is. 4. - P. 536-539, DOI 10.1134/S106287382370627X. - Cited References: 10 . - ISSN 1062-8738. - ISSN 1934-9432
Аннотация: Ferrihydrite nanoparticles are synthesized and characterized. The dependences of heating of powders are studied upon pumping by a high-frequency electromagnetic field on a dc magnetic field. It is shown that the experimental dependence of the temperature of particles on a dc magnetic field is consistent with the theory of ferromagnetic resonance for an isotropic superparamagnet.

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Federal Research Center “Krasnoyarsk Science Center,” Siberian Branch, Russian Academy of Sciences, 660036, Krasnoyarsk, Russia
Siberian Federal University, 660041, Krasnoyarsk, Russia
Kirensky Institute of Physics, Federal Research Center “Krasnoyarsk Science Center,” Siberian Branch, Russian Academy of Sciences, 660036, Krasnoyarsk, Russia

Доп.точки доступа:
Stolyar, S. V.; Столяр, Сергей Викторович; Li, O. A.; Vorotynov, A. M.; Воротынов, Александр Михайлович; Velikanov, D. A.; Великанов, Дмитрий Анатольевич; Maksimov, N. G.; Iskhakov, R. S.; Исхаков, Рауф Садыкович; Ladygina, V. P.; Shokhrina, A. O.
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Interparticle magnetic interactions and magnetic field dependence of superparamagnetic blocking temperature in ferrihydrite nanoparticle powder systems / A. A. Krasikov, Yu. V. Knyazev, D. A. Balaev [et al.] // Phys. B: Condens. Matter. - 2023. - Vol. 660. - Ст. 414901, DOI 10.1016/j.physb.2023.414901. - Cited References: 66. - This study was supported by his work was supported by the Russian Science Foundation, project no. 22-72-00134 . - ISSN 0921-4526. - ISSN 1873-2135
Кл.слова (ненормированные):
Ferrihydrite nanoparticles -- Interparticle magnetic interactions -- Superparamagnetic blocking temperature -- Coating -- Arabinogalactan
Аннотация: In this study, nanoparticles of initial synthetic ferrihydrite have been coated with arabinogalactan. The synthesized series of samples with different degrees of coverage of particles has been characterized by X-ray photoelectron spectroscopy, Mossbauer spectroscopy, transmission electron microscopy and magnetometry. The superparamagnetic blocking temperature decreases monotonically with an increase in the degree of coverage of ferrihydrite particles, which is unambiguously related to the different role of the interparticle magnetic interactions in the investigated powder systems. Analysis of the field dependence of the blocking temperature within the random anisotropy model has shown that an increase in the degree of coverage of ferrihydrite particles leads to a decrease in the size of a cluster in which the behaviors of the nanoparticle magnetic moments are correlated. The results obtained have shown the possibility of effective control of the strength of magnetic interparticle interactions in powder ferrihydrite systems by coating nanoparticles with arabinogalactan.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036 Russia
Siberian Federal University, Krasnoyarsk, 660041, Russia
Krasnoyarsk Scientific Center, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036, Russia
Institute of Chemistry and Chemical Technology, Federal Research Center KSC SB RAS, Krasnoyarsk, 660036 Russia

Доп.точки доступа:
Krasikov, A. A.; Красиков, Александр Александрович; Knyazev, Yu. V.; Князев, Юрий Владимирович; Balaev, D. A.; Балаев, Дмитрий Александрович; Velikanov, D. A.; Великанов, Дмитрий Анатольевич; Stolyar, S. V.; Столяр, Сергей Викторович; Mikhlin, Yu. L.; Yaroslavtsev, R. N.; Ярославцев, Роман Николаевич; Iskhakov, R. S.; Исхаков, Рауф Садыкович
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Spin dynamics in ensembles of ultrafine ferrihydrite nanoparticles / Yu. V. Knyazev, D. A. Balaev, S. A. Skorobogatov [et al.] // Phys. Rev. B. - 2023. - Vol. 107, Is. 11. - Ст. 115413, DOI 10.1103/PhysRevB.107.115413. - Cited References: 66. - The electron microscopy study and ac susceptibility measurements were carried out on the equipment of the Krasnoyarsk Territorial Center for Collective Use, Krasnoyarsk Scientific Center, Siberian Branch of the Russian Academy of Sciences. This study was supported by the Russian Science Foundation, Project No. 21-72-00025 Tuning the Magnetic Properties of Ultrafine Biocompatible Ferrihydrite Nanoparticles through Interparticle Interactions [66] . - ISSN 2469-9950. - ISSN 2469-9969
Аннотация: Features of the spin dynamics in ensembles of interacting (FH-chem) and weakly interacting (FH-coated) magnetic ultrasmall (‹d› ∼ 2 nm) ferrihydrite nanoparticles have been explored. The dc and ac magnetic susceptibilities [χ'(T ) and χ''(T )] of the investigated samples have been thoroughly measured in a weak magnetic field (2 Oe) around the temperatures of superparamagnetic blocking of the nanoparticle magnetic moments (19 and 50.4 K for FH-coated and FH-chem, respectively, according to the dc magnetization data). It has been shown that the magnetic interactions between nanoparticles induce the formation of the cluster spin-glass state below the superparamagnetic blocking temperature (Tg = 18 and 49.5 K for FH-coated and FH-chem, respectively). It has been found that coating of nanoparticles increases the critical scaling index from zν = 5.9 (FH-chem) to zν = 8.0 (FH-coated). This indicates a general slowdown of the dynamics of correlated spins, which is also expressed as an increase in relaxation time τ0 after switching on the interparticle interactions. We attribute this phenomenon to a consequence of a change in the volume of correlated spins with the increasing size of a cluster of interacting nanoparticles. It has been demonstrated using the simulated χ''(T ) dependence that the dissipation of the magnetic energy occurs in two independent stages. The first stage is directly related to the blocking of the nanoparticle magnetic moments, while the second stage reflects the spin-glass behavior of surface spins and depends strongly on the intensity of the interparticle interactions.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Akademgorodok 50, bld. 38, Krasnoyarsk 660036, Russia
Siberian Federal University, Svobodniy 79, Krasnoyarsk 660041, Russia

Доп.точки доступа:
Knyazev, Yu. V.; Князев, Юрий Владимирович; Balaev, D. A.; Балаев, Дмитрий Александрович; Skorobogatov, S. A.; Скоробогатов, Станислав Алексеевич; Velikanov, D. A.; Великанов, Дмитрий Анатольевич; Bayukov, O. A.; Баюков, Олег Артемьевич; Stolyar, S. V.; Столяр, Сергей Викторович; Yaroslavtsev, R. N.; Ярославцев, Роман Николаевич; Iskhakov, R. S.; Исхаков, Рауф Садыкович
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Magnetic interparticle interactions and superparamagnetic blocking of powder systems of biogenic ferrihydrite nanoparticles / A. A. Krasikov, Yu. V. Knyazev, D. A. Balaev [et al.] // J. Exp. Theor. Phys. - 2023. - Vol. 137, Is. 6. - P. 903-913, DOI 10.1134/S1063776123120075. - Cited References: 58. - This study was supported by the Russian Science Foundation, project no. 22-72-00134 . - ISSN 1063-7761. - ISSN 1090-6509
Аннотация: The magnetic-field dependence of the superparamagnetic-blocking temperature TB of systems of antiferromagnetically ordered ferrihydrite nanoparticles has been investigated and analyzed. We studied two powder systems of nanoparticles: particles of “biogenic” ferrihydrite (with an average size of 2.7 nm), released as a result of vital functions of bacteria and coated with a thin organic shell, and particles of biogenic ferrihydrite subjected to low-temperature annealing, which cause an increase in the average particle size (to 3.8 nm) and burning out of the organic shell. The character of the temperature dependences of magnetization, measured after cooling in a weak field, as well as the shape of the obtained dependences TB(H), demonstrate peculiar features, indicating the influence of magnetic interparticle interactions. A detailed analysis of the dependences TB(H) within the random magnetic anisotropy model made it possible to estimate quantitatively the intensity of magnetic particle–particle interactions and determine the magnetic anisotropy constants of individual ferrihydrite particles.

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Публикация на русском языке Магнитные межчастичные взаимодействия и суперпарамагнитная блокировка порошковых систем наночастиц биогенного ферригидрита [Текст] / А. А. Красиков, Ю. В. Князев, Д. А. Балаев [и др.]. - 13 с. // Журн. эксперим. и теор. физ. - 2023. - Т. 164 Вып. 6. - С. 1026-1038

Держатели документа:
Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, 660036, Akademgorodok, Krasnoyarsk, Russia
Federal Research Center “Krasnoyarsk Science Center of the Siberian Branch of the Russian Academy of Sciences”, 660036, Krasnoyarsk, Russia

Доп.точки доступа:
Krasikov, A. A.; Красиков, Александр Александрович; Knyazev, Yu. V.; Князев, Юрий Владимирович; Balaev, D. A.; Балаев, Дмитрий Александрович; Stolyar, S. V.; Столяр, Сергей Викторович; Ladygina, V. P.; Balaev, A. D.; Балаев, Александр Дмитриевич; Iskhakov, R. S.; Исхаков, Рауф Садыкович
}
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    Superparamagnetic relaxation in ensembles og ultrasmall ferrihydrite nanoparticles / D. A. Balaev, S. A. Skorobogatov, D. A. Velikanov [et al.] // Магнитные материалы. Новые технологии : тез. докл. IX Байкал. междунар. конф. BICMM-2023 / чл. прогр. ком.: S. S. Aplesnin [et al.] ; чл. орг. ком. R. S. Iskhakov [et al.]. - Иркутск, 2023. - P. 92. - Библиогр.: 1 . - ISBN 978-5-962402178-0
   Перевод заглавия: Спиновая динамика в ансамблях ультрамалых ферричастиц ферригидрита

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Держатели документа:
Сибирский федеральный университет
Институт физики им. Л. В. Киренского СО РАН

Доп.точки доступа:
Аплеснин, Сергей Степанович \чл. прогр. ком.\; Aplesnin, S. S.; Балаев, Дмитрий Александрович \чл. прогр. ком.\; Balaev, D. A.; Овчинников, Сергей Геннадьевич \чл. прогр. ком.\; Ovchinnikov, S. G.; Исхаков, Рауф Садыкович \чл. орг. ком.\; Iskhakov, R. S.; Балаев, Дмитрий Александрович; Skorobogatov, S. A.; Velikanov, D. A.; Великанов, Дмитрий Анатольевич; Bayukov, O. A.; Баюков, Олег Артемьевич; Stolyar, S. V.; Столяр, Сергей Викторович; Yaroslavtsev, R. N.; Ярославцев, Роман Николаевич; Исхаков, Рауф Садыкович; Knyazev, Yu. V.; Князев, Юрий Владимирович; Байкальская международная конференция "Магнитные материалы. Новые технологии"(9 ; 2023 ; сент. ; 11-14 ; Байкальск); "Магнитные материалы. Новые технологии", Байкальская международная конференция(9 ; 2023 ; сент. ; 11-14 ; Байкальск); "Magnetic materials. New tecnologies", Baikal International Conference(9 ; 2023 ; Sept. ; 11-14 ; Baikalsk); Иркутский государственный университет
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Role of the surface effects and interparticle magnetic interactions in the temperature evolution of magnetic resonance spectra of ferrihydrite nanoparticle ensembles / D. A. Balaev, S. V. Stolyar, Y. V. Knyazev [et al.] // Results Phys. - 2022. - Vol. 35. - Ст. 105340, DOI 10.1016/j.rinp.2022.105340. - Cited References: 119. - Authors thank to A.D. Balaev, S.V. Komogortsev for fruitful discussions and M.N. Volochaev for TEM studies. The TEM study and measurements of X-band FMR spectra were carried out on the equipment of the Krasnoyarsk Territorial Center for Collective Use, Krasnoyarsk Scientific Center, Siberian Branch, Russian Academy of Sciences. This study was supported by the Russian Science Foundation, project no. 21-72-00025 (https://rscf.ru/project/21-72-00025/) "Tuning the Magnetic Properties of Ultrafine Biocompatible Ferrihydrite Nanoparticles through Interparticle Interactions" . - ISSN 2211-3797
Кл.слова (ненормированные):
Ferrihydrite nanoparticles -- Superparamagnetism -- Interparticle magnetic interactions -- Ferromagnetic resonance
Аннотация: Ferrihydrite is characterized by the antiferromagnetic ordering and, in ferrihydrite nanoparticles, as in nanoparticles of any antiferromagnetic material, an uncompensated magnetic moment is formed. We report on the investigations of ferrihydrite powder systems with an average particle size of ∼ 2.5 nm obtained (i) as a product of the vital activity of bacteria (sample FH-bact) and (ii) by a chemical method (sample FH-chem). In the first approximation, these samples can be considered to be identical. However, in sample FH-chem, particles contact directly, while in sample FH-bact, they have organic shells; therefore, the interparticle magnetic interactions in these samples have different degrees. The main goal of this work has been to establish the effects of the interparticle magnetic interactions and individual characteristics of ferrihydrite nanoparticles on ferromagnetic resonance (FMR) spectra. The FMR spectra have been measured at different (9.4–75 GHz) frequencies in a wide temperature range. It has been found that, at low temperatures, the field-frequency dependence ν(HR) of the investigated systems has a gap ν/γ = HR + HA, where HR is the resonance field and HA is the induced anisotropy, which decreases with increasing temperature. To estimate a degree of the effect of interparticle interactions on the results obtained and to correctly determine the temperature range of the superparamagnetic (or blocked) state, the static magnetic measurement and Mössbauer spectroscopy data have been obtained and analyzed. It has been shown that the most striking feature of the FMR spectra - a gap in the field-frequency dependences - is a manifestation of individual characteristics of ferrihydrite nanoparticles. The induced anisotropy is caused by freezing of a subsystem of surface spins and its coupling with the particle core, which is observed in both samples at a temperature of ∼80 K. The temperature range (below 80 K) in which the gap exists corresponds to the blocked state in the FMR technique. In sample FH-bact, the ratio between the FMR parameters HA and linewidth ΔH obeys the standard expression HA ∼ (ΔH)3. In sample FH-chem, however, the interparticle magnetic interactions dramatically affect the behavior of parameters of the FMR spectra, which change nonmonotonically upon temperature variation. This fact is attributed to the collective freezing of the magnetic moments of particles under the conditions of sufficiently strong interactions, which follows from the temperature dependence of the particle magnetic moment relaxation time determined from the Mössbauer spectroscopy and static magnetometry data obtained in weak magnetic fields.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Akademgorodok 50, bld. 38, Krasnoyarsk, 660036, Russian Federation
Siberian Federal University, Svobodniy 79, Krasnoyarsk, 660041, Russian Federation
Krasnoyarsk Scientific Center, Federal Research Center KSC SB RAS, Akademgorodok 50, Krasnoyarsk, 660036, Russian Federation

Доп.точки доступа:
Balaev, D. A.; Балаев, Дмитрий Александрович; Stolyar, S. V.; Столяр, Сергей Викторович; Knyazev, Yu. V.; Князев, Юрий Владимирович; Yaroslavtsev, R. N.; Ярославцев, Роман Николаевич; Pankrats, A. I.; Панкрац, Анатолий Иванович; Vorotynov, A. M.; Воротынов, Александр Михайлович; Krasikov, A. A.; Красиков, Александр Александрович; Velikanov, D. A.; Великанов, Дмитрий Анатольевич; Bayukov, O. A.; Баюков, Олег Артемьевич; Ladygina, V. P.; Iskhakov, R. S.; Исхаков, Рауф Садыкович
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Ferrihydrite nanoparticles produced by Klebsiella oxytoca: Structure and properties dependence on the cultivation time / S. V. Stolyar, O. A. Bayukov, D. A. Balaev [et al.] // Adv. Powder Technol. - 2022. - Vol. 33, Is. 8. - Ст. 103692, DOI 10.1016/j.apt.2022.103692. - Cited References: 59. - This work was supported by Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Region Science and Technology Support Fund to the research projects No. 20-416-242907 . - ISSN 0921-8831
Кл.слова (ненормированные):
Ferrihydrite nanoparticles -- Structure -- Microbial synthesis -- Mössbauer spectroscopy -- Small-angle X-ray scattering
Аннотация: Ferrihydrite nanoparticles were synthesized using Klebsiella oxytoca microorganisms under various cultivation conditions. The cultivation of bacteria was carried out under various lighting conditions, and the duration of cultivation varied from 3 to 56 days. Biogenic ferrihydrite nanoparticles were studied by Mössbauer spectroscopy, magnetometry, and small-angle X-ray scattering. The process of formation of ferrihydrite nanoparticles and the states arising during the cultivation of microorganisms have been investigated. The results of Mössbauer spectroscopy showed that, depending on the time of cultivation, three different states of ferrihydrite can be realized. States differ both in the ratio of defective and non-defective positions, and the size of the particle. Experimental results indicate that ferrihydrite nanoparticles are a system of variable composition and pass through several structural (or morphological) states during the cultivation of microorganisms. A model of the structure of ferrihydrite nanoparticles is proposed, which consists in the presence of an antiferromagnetic dense core with a high Néel temperature and a friable shell with a significantly lower temperature of magnetic ordering.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Krasnoyarsk, Russian Federation
Krasnoyarsk Scientific Center, Federal Research Center KSC SB RAS Krasnoyarsk, Russian Federation
Siberian Federal University, Krasnoyarsk, Russian Federation
Joint Institute for Nuclear Research, Dubna, Russian Federation

Доп.точки доступа:
Stolyar, S. V.; Столяр, Сергей Викторович; Bayukov, O. A.; Баюков, Олег Артемьевич; Balaev, D. A.; Балаев, Дмитрий Александрович; Ladygina, V. P.; Yaroslavtsev, R. N.; Ярославцев, Роман Николаевич; Knyazev, Yu. V.; Князев, Юрий Владимирович; Balasoiu, M.; Kolenchukova, O. A.; Iskhakov, R. S.; Исхаков, Рауф Садыкович
}
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10.

Interparticle magnetic interactions in synthetic ferrihydrite: Mossbauer spectroscopy and magnetometry study of the dynamic and static manifestations / Y. V. Knyazev, D. A. Balaev, S. V. Stolyar [et al.] // J. Alloys Compd. - 2022. - Vol. 889. - Ст. 161623, DOI 10.1016/j.jallcom.2021.161623. - Cited References: 84. - This study was supported by the Russian Foundation for Basic Research, the Government of the Krasnoyarsk Territory, and the Krasnoyarsk Territorial Foundation for Support of Scientific and R&D Activities, project no. 19–42–240012 R-A “Magnetic Resonance in Ferrihydrite Nanoparticles: Effects Related to the Core-Shell Structure” . - ISSN 0925-8388
Кл.слова (ненормированные):
Ferrihydrite nanoparticles -- Superparamagnetism -- Interparticle magnetic interactions
Аннотация: Samples of synthetic ferrihydrite with an average nanoparticle size of 2.7 nm have been examined by magnetometry and Mossbauer spectroscopy. Ferrihydrite is characterized by the antiferromagnetic interactions between the magnetic moments of iron atoms. In ferrihydrite nanoparticles, as in any other antiferromagnetic ones, structural defects induce the formation of an uncompensated magnetic moment, which determines the magnetic properties typical of single-domain ferro- and ferrimagnetic particles. The manifestation of the magnetic interactions between ferrihydrite nanoparticles in the magnetic properties of the material and in the temperature evolution of Mossbauer spectra has been in focus. The results obtained on synthetic ferrihydrite have been compared with the data for the biogenic ferrihydrite sample with a similar average size of particles surrounded by a polysaccharide shell, which weakens and screens the interparticle magnetic interactions. A clear manifestation of the effect of the interparticle magnetic interactions on the transition to the blocked state is the presence of a significant contribution of the relaxation component in the Mossbauer spectra at temperatures of the transition from the superparamagnetic to blocked state. The temperature dependence of the particle relaxation time obtained from the Mossbauer spectra points out the collective effect of freezing of the magnetic moments of particles due to the magnetic interactions between them.

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Держатели документа:
Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Akademgorodok 50, bld. 38, Krasnoyarsk, 660036, Russian Federation
Siberian Federal University, Svobodniy 79, Krasnoyarsk, 660041, Russian Federation
Krasnoyarsk Scientific Center, Federal Research Center KSC SB RAS, Akademgorodok 50, Krasnoyarsk, 660036, Russian Federation

Доп.точки доступа:
Knyazev, Yu. V.; Князев, Юрий Владимирович; Balaev, D. A.; Балаев, Дмитрий Александрович; Stolyar, S. V.; Столяр, Сергей Викторович; Krasikov, A. A.; Красиков, Александр Александрович; Bayukov, O. A.; Баюков, Олег Артемьевич; Volochaev, M. N.; Волочаев, Михаил Николаевич; Yaroslavtsev, R. N.; Ярославцев, Роман Николаевич; Ladygina, V. P.; Velikanov, D. A.; Великанов, Дмитрий Анатольевич; Iskhakov, R. S.; Исхаков, Рауф Садыкович
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