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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Stolyar S. V., Bayukov O. A., Chekanova L. A., Gerasimova Y. V., Sokolov A. Е., Iskhakov R. S., Yaroslavtsev R. N., Volochaev M. N., Artemyeva A. S., Cheremiskina E. V., Knyazev Yu. V.
Заглавие : Anisometric iron oxide-based nanoparticles and sols based on them: Preparation and properties
Место публикации : J. Supercond. Novel Magn. - 2019. - Vol. 32, Is. 4. - P.971–975. - ISSN 15571939 (ISSN) , DOI 10.1007/s10948-018-4784-7
Примечания : Cited References: 18. - The reported study was carried out with the financial support of the Russian Foundation for Fundamental Research, the Government of the Krasnoyarsk Territory, and the Krasnoyarsk Territory Fund for Support of Scientific and Technical Activity in the framework of scientific Projects No. 18-43-243003, No. 17-42-240080 and No. 17-43-240527. The work is supported by the Special Program of the Ministry of Education and Science of the Russian Federation for the Siberian Federal University.
Ключевые слова (''Своб.индексиров.''): nanoparticles and nanorods--chemical preparation--superparamagnetism
Аннотация: We have synthesized magnetic powders of the magnetite-maghemite series by the chemical reaction of the FeSO4 iron salt and the natural arabinogalactan polysaccharide. These particles with a high magnetization value (∼ 300 Gs) represent a mixture of spherical particles and nanorods. Particles of a spherical shape (diameter of ∼ 5–6 nm) show a superparamagnetic behavior at room temperature, while rods with a diameter of ∼ 5 nm and a length of 30 nm are magnetic. We have prepared sol samples based on the nanoparticle aqueous solution of arabinogalactan. Our results on the magnetism of the circular dichroism (MCD) on sol are consistent with the of Mössbauer spectroscopy data.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Poperechny I. S., Krasikov A. A., Semenov S. V., Popkov S. I., Knyazev Yu. V., Kirillov V. L., Yakushkin S. S., Martyanov O. N., Raikher Y. L.
Заглавие : Dynamic remagnetisation of CoFe2O4 nanoparticles: thermal fluctuational thawing of anisotropy
Коллективы : [AAAA-A17-117103050081-1]; [AAAAA20-120020690030-5]
Место публикации : J. Phys. D. - 2021. - Vol. 54, Is. 27. - Ст.275003. - ISSN 0022-3727, DOI 10.1088/1361-6463/abf371. - ISSN 1361-6463(eISSN)
Примечания : Cited References: 63. - Experimental measurements were supported by Project No. AAAA-A17-117103050081-1. I S P and Yu L R acknowledge the support of ICMM in the framework of topical task AAAAA20-120020690030-5. The numerical calculations were performed on the Uran supercomputer (Ural Branch, Russian Academy of Sciences, Ekaterinburg)
Предметные рубрики: COBALT-FERRITE NANOPARTICLES
MAGNETIC-PROPERTIES
SIZE
COERCIVITY
Аннотация: We report a study of the magnetodynamics of cobalt ferrite (CoFe2O4) nanoparticles with an average diameter of ~6 nm. Hysteresis loops were measured under quasi-static conditions and in pulse fields with amplitudes H0 of up to 130 kOe and for durations τP of 8 and 16 ms. The growth of coercivity Hc observed with an increase in the magnetic field variation rate dH/dt (determined by the values of H0 and τP) and the reduction of Hc with temperature is ascribed to the superparamagnetic effect. The proposed theoretical model explains the observed dependences fairly well. Notably, the effective magnetic anisotropy constant obtained exceeds the value for bulk crystals and might be indicative of the contribution of surface magnetic anisotropy.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kliava J., Edelman I. S., Ivanova O. S., Ivantsov R. D., Bayukov O. A., Petrakovskaja E. A., Zaikovskiy V., Bruckental I., Yeshurun Y., Stepanov S.
Заглавие : Formation and evolution of magnetic nanoparticles in borate glass simultaneously doped with Fe and Mn oxides
Коллективы :
Место публикации : J. Appl. Phys.: AMER INST PHYSICS, 2008. - Vol. 104, Is. 10. - Ст.103917. - ISSN 0021-8979, DOI 10.1063/1.3021289
Примечания : Cited References: 37. - A financial support from the Russian Foundation for Basic Research (RFBR)-CNRS (Grant No. 07-02-92174) is highly appreciated. R. Ivantsov is grateful to the Russian Science Support Foundation. Y. Yeshurun acknowledges the support of the Israel Scienc Foundation (ISF).
Предметные рубрики: COBALT FERRITE PARTICLES
SUPERPARAMAGNETIC RESONANCE
GAMMA-FE2O3 NANOPARTICLES
MATRIX
SIZE
SYSTEMS
Ключевые слова (''Своб.индексиров.''): aluminium compounds--borate glasses--coercive force--faraday effect--heat treatment--iron compounds--magnetic hysteresis--magnetic particles--magnetic susceptibility--manganese compounds--mossbauer effect--nanoparticles--paramagnetic materials--potassium compounds--remanence--superparamagnetism--transmission electron microscopy--x-ray chemical analysis--atomic spectroscopy--auger electron spectroscopy--crystal structure--electric relays--electronic medical equipment--ferrite--ferrites--glass--heat treatment--hysteresis--hysteresis loops--magnetic properties--magnetic resonance measurement--magnetic susceptibility--magnetism--manganese--manganese compounds--molybdenum--nanoparticles--optical properties--ozone water treatment--polydispersity--superparamagnetism--borate glasses--concentration ratios--electron magnetic resonances--emr spectrums--experimental techniques--faraday rotations--glass compositions--glass matrixes--glass preparations--magnetic measurements--magnetic nano particles--magnetic orders--magnetically ordered systems--magneto-optical properties--manganese ferrites--mean diameters--mn oxides--phase states--polydisperse nanoparticles--remnant magnetizations--ssbauer spectroscopies--superparamagnetic--superparamagnetic states--thermal treatments--variable temperatures--magnetic materials
Аннотация: Evolution of the phase state of paramagnetic additions at various stages of synthesis and subsequent thermal treatment of glasses of the system Al(2)O(3)-K(2)O-B(2)O(3) simultaneously doped with Fe(2)O(3) and MnO is studied by means of a combination of experimental techniques: Faraday rotation (FR), electron magnetic resonance (EMR), transmission electron microscopy (TEM), Mossbauer spectroscopy, and magnetic measurements. Both FR and EMR show that magnetically ordered clusters occur already at the first stage of the glass preparation. In particular, for the ratio of the Fe and Mn oxides in the charge close to 3:2, fine magnetic nanoparticles are formed with characteristics similar to those of manganese ferrite. By computer simulating the EMR spectra at variable temperatures, a superparamagnetic nature of these nanoparticles is confirmed and their mean diameter is estimated as approximately 3.2 nm. In the thermally treated glasses larger magnetic nanoparticles are formed, giving rise to FR spectra, characteristic of magnetically ordered systems, and the EMR spectra different from those in as-prepared glasses but also showing superparamagnetic narrowing. The Mossbauer spectroscopy corroborates the manganese ferrite structure of the nanoparticles and indicates their coexistence in the ferrimagnetic and superparamagnetic states. The TEM shows the presence of polydisperse nanoparticles on the background of the glass matrix, and electron diffraction of a selected region containing larger particles indicates a crystal structure close to that of MnFe(2)O(4). Energy-dispersive atomic x-ray spectra confirm that the major part of Fe and Mn introduced to the glass composition is gathered in the particles, with the concentration ratio close to 2:1, characteristic of bulk MnFe(2)O(4). Magnetic hysteresis loops of samples subjected to an additional thermal treatment demonstrate a strong increase in the coercive force, remnant magnetization, and high-field magnetic susceptibility with temperature decrease. The consistent results obtained using various techniques demonstrate that the formation of nanoparticles with characteristics close to those of MnFe(2)O(4) confers to these glasses magnetic and magneto-optical properties typical of substances possessing magnetic order.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Knyazev Yu. V., Balaev D. A., Stolyar S. V., Krasikov A. A., Bayukov O. A., Volochaev M. N., Yaroslavtsev R. N., Ladygina V. P., Velikanov D. A., Iskhakov R. S.
Заглавие : Interparticle magnetic interactions in synthetic ferrihydrite: Mossbauer spectroscopy and magnetometry study of the dynamic and static manifestations
Место публикации : J. Alloys Compd. - 2022. - Vol. 889. - Ст.161623. - ISSN 09258388 (ISSN), DOI 10.1016/j.jallcom.2021.161623
Примечания : 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”
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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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Stolyar S. V., Komogortsev S. V., Gorbenko A. S., Knyazev Yu. V., Yaroslavtsev R. N., Olkhovskiy I. A., Neznakhin D. S., Tyumentseva A. V., Bayukov O. A., Iskhakov R. S.
Заглавие : Maghemite nanoparticles for DNA extraction: Performance and blocking temperature
Место публикации : J. Supercond. Novel Magn. - 2022. - Vol. 35, Is. 7. - P.1929-1936. - ISSN 15571939 (ISSN), DOI 10.1007/s10948-022-06233-5
Примечания : Cited References: 33. - This work was supported by Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Region Science and Technology Support Fund, with research projects no. 20–42-242902. We are grateful to the Center of Collective Use of FRC KSC SB RAS for the provided equipment
Аннотация: Iron oxide nanoparticles coated with polyethylene glycol were synthesized by coprecipitation for use in the magnetic separation of DNA (deoxyribonucleic acid). The blocking temperature of nanoparticles was studied by the methods of Mossbauer spectroscopy, ferromagnetic resonance, and using magnetometric measurements. The blocking temperature calculated from the temperature dependence of the coercive force was ~ 200 K. The calculation of the blocking temperature from the relaxation time obtained using Mossbauer spectroscopy gave a value of ~ 450 K. The blocking temperature obtained using ferromagnetic resonance was ~ 910 K. The relationship between the obtained blocking temperatures is in good agreement with the Neel-Brown formula. The constants of effective and surface anisotropy were determined by the method of ferromagnetic resonance. Isolation of DNA from blood using prepared particles and separation in a permanent magnet field revealed sufficient productivity, high speed, and the “chemical delicacy” of this approach.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrov D. A., Ivantsov R. D., Zharkov S. M., Velikanov D. A., Molokeev M. S., Lin C. -R., Tso C. -T., Hsu H. -S., Tseng Y. -T., Lin E. -S., Edelman I. S.
Заглавие : Magnetic and magneto-optical properties of Fe3O4 nanoparticles modified with Ag
Место публикации : J. Magn. Magn. Mater. - 2020. - Vol. 493. - Ст.165692. - ISSN 03048853 (ISSN), DOI 10.1016/j.jmmm.2019.165692
Примечания : Cited References: 45. - The reported study was funded by Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Regional Fund of Science to the research project № 18-42-243021 and by Joint Research Project of Russian Foundation for Basic Research № 19-52-52002 and Ministry of Science and Technology, Taiwan MOST № 108-2923-M-153-001-MY3 and № 106-2112-M-153-001-MY3.
Аннотация: Effect of Ag inclusions on magnetic properties and magnetic circular dichroism (MCD) of Fe3O4 nanoparticles (NPs) in the mixed system of Fe3O4 and Ag NPs in dependence on the relative concentration of the components is presented. The samples were synthesized by the thermal decomposition of the mixture of constant concentration of Fe(NO3)3·9H2O and varied concentration of AgNO3. The synthesized powdered samples consisted of Fe3O4 and Ag NPs located very close with each other, and in the most cases the Fe3O4 NPs were bordered with the Ag nanocrystals. The Ag introducing in the samples does not effect, practically, in the Fe3O4 NPs morphology and size distribution. At the same time, Ag NPs in the powdered samples cause a decrease in the Fe3O4 NPs magnetization and shift of the blocking temperature to lower temperatures, both approximately proportional to the Ag concentration. Most significant changes are revealed in the MCD spectra in the energy region of 1.2–2.2 eV. We have discussed the influence of the Ag NPs on the MCD spectra features in terms of the charge-transfer electron transitions. © 2019 Elsevier B.V.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Knyazev Yu. V., Balaev D. A., Stolyar S. V., Bayukov O. A., Yaroslavtsev R. N., Ladygina V. P., Velikanov D. A., Iskhakov R. S.
Заглавие : Magnetic anisotropy and core-shell structure origin of the biogenic ferrihydrite nanoparticles
Место публикации : J. Alloys Compd. - 2021. - Vol. 851. - Ст.156753. - ISSN 09258388 (ISSN), DOI 10.1016/j.jallcom.2020.156753
Примечания : Cited References: 82. - The electron microscopy study was 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 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 p-a “Magnetic Resonance in Ferrihydrite Nanoparticles: Effects Related to the Core–Shell Structure”
Аннотация: Ferrihydrite is a low-crystalline nanoscale matter. The uncompensated magnetic moment of the ferrihydrite caused by the antiferromagnetic ordering of the magnetic moments of iron atoms and leads to the magnetic properties very similar to those of ferro- and ferrimagnetic nanoparticles. In this study, we investigated the biogenic ferrihydrite nanoparticles with the narrow size distribution and an average diameter of ≈2 nm obtained by the bacteria life cycle. The features caused by the surface effects and the inhomogeneous structure of ferrihydrite have been examined in the temperature range of 4–300 K using Mossbauer spectroscopy and magnetometry. Based on the Mossbauer data, we identified the superparamagnetic blocking temperature at the temperature of 30 K for the largest ferryhidrite particles. We established that the exceptional magnetic anisotropy of ferrihydrite (KV=1.2∙105 erg/cm3 and KS=0.1 erg/cm2) is reached because of the highly developed ferrihydrite nanoparticles’ surface. According to the Mossbauer data, we propose a core-shell structural model of the biogenic ferrihydrite particles. We found that the size of the dense core depends on the particle size. The well-crystallized core is formed only for nanoparticles larger than ≈2 nm, whereas smaller particles consist entirely of a matter with a lower density of iron atoms.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Yurkin G. Yu., Patrin G. S., Yarikov, Stanislav A.
Заглавие : Magnetic Properties of Fe1-xCoxSi Single Crystals at Low Co Impurity Concentrations
Место публикации : J. Sib. Fed. Univ. Math. Phys. - 2019. - Vol. 12, Is. 1. - P.94-99. - ISSN 1997-1397, DOI 10.17516/1997-1397-2019-12-1-94-99; \b Журнал СФУ. Математика и физика. - ISSN 2313-6022(eISSN)
Примечания : Cited References: 17
Ключевые слова (''Своб.индексиров.''): co impurities--iron silicide--superparamagnetism--силицид железа--примесь co--суперпарамагнетизм
Аннотация: Magnetostatic properties of FeSi and Fe0,98Co0,02Si single crystals have been studied. It has been found that the temperature and field dependences of the magnetization of monocrystal FeSi are strongly affected by introduction of a small amount of Co (2 %). A description of the results were provided by a model accounting for the formation of superparamagnetic iron clusters, as well as Fe-Co complexes. It is assumed that Fe-Co complexes form a ferromagnetic phase, which is approximately 0.6% of the Fe0,98Co0,02Si sample weight.В работе представлено исследование магнитостатических характеристик образцов FeSi и Fe0,98Co0,02Si. Обнаружено, что внесение небольшого количества примести Co(2%) значительно влияет на температурные и полевые зависимости намагниченности монокристалла FeSi. Результаты обработаны в рамках модели, учитывающей образование суперпарамагнитных кластеров железа, а также комплексов Fe-Co. Предполагается, что комплексы Fe-Co образуют ферромагнитную фазу, которая составляет примерно 0,6 % от массы образца Fe0,98Co0,02Si.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Yurkin G. Yu., Patrin G. S., Yarikov S. A.
Заглавие : Magnetic Properties of Fe1-xCoxSi Single Crystals at Low Co Impurity Concentrations
Место публикации : J. Sib. Fed. Univ. Math. Phys. - 2019. - Vol. 12, Is. 6. - P.756-771. - ISSN 1997-1397, DOI 10.17516/1997-1397-2019-12-1-1-6; Журн. СФУ. Матем. и физика. - ISSN 2313-6022 (eISSN)
Примечания : Cited References: 17
Аннотация: Velocity of bulk acoustic waves in base and rotated cuts have been measured by the ultrasonic pulse-echo method and values of CE ijkl and eijk in single crystals YAl3(BO3)4 have been calculated. The value of dijk piezoelectric modulus of these single crystals have been determined by quasistatic measurements, and εσ ij dielectric constants have been determined by the flat capacitor method. Experimental values of material constants have been applied for the study of Magnetostatic properties of FeSi and Fe0;98Co0;02Si single crystals have been studied. It has been found that the temperature and field dependences of the magnetization of monocrystal FeSi are strongly affected by introduction of a small amount of Co (2 %). A description of the results were provided by a model accounting for the formation of superparamagnetic iron clusters, as well as Fe-Co complexes. It is assumed that Fe-Co complexes form a ferromagnetic phase, which is approximately 0.6% of the Fe0;98Co0;02Si sample weightВ работе представлено исследование магнитостатических характеристик образцов FeSi и Fe0;98Co0;02Si. Обнаружено, что внесение небольшого количества примести Co (2 %) значительно влияет на температурные и полевые зависимости намагниченности монокристалла FeSi. Результаты обрабобтаны в рамках модели, учетывающей образование суперпарамагнитных кластеров железа, а также комплексов Fe-Co. Предполагается, что комплексы Fe-Co образуют ферромагнитную фазу, которая составляет примерно 0,6 % от массы образца Fe0;98Co0;02Si.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Krasikov A. A., Dubrovskiy A. A., Popkov S. I., Stolyar S. V., Bayukov O. A., Iskhakov R. S., Ladygina V. P., Yaroslavtsev R. N.
Заглавие : Magnetic properties of heat treated bacterial ferrihydrite nanoparticles
Место публикации : J. Magn. Magn. Mater.: Elsevier, 2016. - Vol. 410. - P.171-180. - ISSN 03048853 (ISSN), DOI 10.1016/j.jmmm.2016.02.059
Примечания : Cited References: 66. - TEM studies were performed on facility of Resource Sharing Center of Krasnoyarsk Scientific Center of Siberian Branch of Russian Academy of Sciences. Authors acknowledge to M.N. Volochaev for the TEM measurements.
Предметные рубрики: Hematite nanoparticles
NiO nanoparticles
Porous-glass
Ferritin
Particles
Temperature
Hysteresis
Transition
Anomalies
Mossbauer
Ключевые слова (''Своб.индексиров.''): ferrihydrite--nanoparticles--superparamagnetism
Аннотация: The magnetic properties of ferrihydrite nanoparticles, which are products of vital functions of Klebsiella oxitoca bacteria, have been studied. The initial powder containing the nanoparticles in an organic shell was subjected to low-temperature (T=160 °C) heat treatment for up to 240 h. The bacterial ferrihydrite particles exhibit a superparamagnetic behavior. Their characteristic blocking temperature increases from 26 to 80 K with the heat treatment. Analysis of the magnetization curves with regard to the magnetic moment distribution function and antiferromagnetic contribution shows that the low-temperature heat treatment enhances the average magnetic moment of a particle; i.e., the nanoparticles coarsen, probably due to their partial agglomeration during heat treatment. It was established that the blocking temperature nonlinearly depends on the particle volume. Therefore, a model was proposed that takes into account both the bulk and surface magnetic anisotropy. Using this model, the bulk and surface magnetic anisotropy constants KV≈1.7×105 erg/cm3 and KS≈0.055 erg/cm2 have been determined. The effect of the surface magnetic anisotropy of ferrihydrite nanoparticles on the observed magnetic hysteresis loops is discussed.
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