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1.

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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2.

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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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kliava J., Malakhovskii A. V., Edelman I. S., Potseluyko A. M., Petrakovskaja E. A., Bruckental I., Yeshurun Y., Zarubina T.
Заглавие : Unusual magnetic phase transitions in Gd3+ clusters in multicomponent oxide glasses
Разночтения заглавия :авие SCOPUS: Unusual magnetic phase transitions in Gd 3+ clusters in multicomponent oxide glasses
Место публикации : J. Supercond. Nov. Magn.: SPRINGER, 2007. - Vol. 20, Is. 2. - P149-153. - ISSN 1557-1939, DOI 10.1007/s10948-006-0116-4
Примечания : Cited References: 7
Предметные рубрики: GADOLINIUM
RESONANCE
Ключевые слова (''Своб.индексиров.''): oxide glasses--gadolinium--magnetic clusters--superparamagnetism--gadolinium--magnetic clusters--oxide glasses--superparamagnetism--magnetic clusters--magnetic phase transitions--oxide glasses--weiss constant--antiferromagnetic materials--ferromagnetic materials--gadolinium--magnetic anisotropy--magnetic susceptibility--paramagnetic resonance--phase transitions--positive ions--superparamagnetism--glass
Аннотация: Magnetic susceptibility, EPR and optical properties have been studied in a glass system {20La(2)O(3) - 22Al(2)O(3) - 23B(2)O(3) - 35(SiO2 + GeO2)} with a part of La2O3 substituted by Gd2O3 in different concentrations. Positive Weiss constants have been found in more heavily doped glasses; two magnetic transitions at 55 and 12 K have been detected and ascribed, respectively, to ferromagnetic and antiferromagnetic clusters of Gd3+ ions. The EPR spectra confirm the clustering at higher Gd contents. At low temperatures the cluster-related resonance indicates an onset of magnetic anisotropy. The clustering, depending on the Gd concentration, correlates with a shift to lower energies of the strong optical absorption band edge.
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrakovskaya E. A., Isakova V. G., Bayukov O. A., Velikanov D. A.
Заглавие : Superparamagnetism of magnetite particles in C-60 fullerite powder
Разночтения заглавия :авие SCOPUS: Superparamagnetism of magnetite particles in C60 fullerite powder
Место публикации : Tech. Phys.: AMER INST PHYSICS, 2005. - Vol. 50, Is. 6. - P790-793. - ISSN 1063-7842, DOI 10.1134/1.1947359
Примечания : Cited References: 9
Предметные рубрики: RESONANCE
Аннотация: A new magnetic material, C-60 fullerite powder doped by magnetite (Fe3O4) nanoparticles, is obtained by heating a mixture of fullerite and iron(III) acetylacetonate. It is shown that the material offers superparamagnetic properties. Surface bonding between the nanoparticles and the fullerite is established. (c) 2005 Pleiades Publishing, Inc.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Edelman I. S., Ivantsov R., Vasiliev A., Stepanov S., Kornilova E., Zarubina T.
Заглавие : Superparamagnetic and ferrimagnetic nanoparticles in glass matrix
Место публикации : Physica B. - 2001. - Vol. 301, Is. 3-4. - P.203-211. - ISSN 0921-4526, DOI 10.1016/S0921-4526(01)00274-5
Примечания : Cited References: 9
Предметные рубрики: MAGNETIC-PROPERTIES
PARTICLES
FILMS
Ключевые слова (''Своб.индексиров.''): magnetic nanoparticles--faraday rotation--faraday rotation--magnetic nanoparticles--crystal structure--faraday effect--ferrimagnetic materials--glass--particle size analysis--superparamagnetism--x ray diffraction analysis--amorphous glass matrices--faraday rotations--nanostructured materials
Аннотация: Faraday rotation (FR) spectral, field, and temperature dependencies in oxide glasses with small additions of paramagnetic elements are investigated. Formation of ferrite nanoparticles in amorphous glass matrices is revealed by X-ray diffraction. Particles have crystal structure similar to spinel structure, their dimensions are about 10-24 nm. The FR field dependencies are typical for ferrimagnetic or superparamagnetic substances depending on particle size. Strong FR increase at the samples cooling (more than twice for some samples) in the temperature interval 105-273 K is observed. (C) 2001 Elsevier Science B.V. All rights reserved.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Vorotynov A. M., Abramova G. M., Popov M. A., Petrakovskii G. A., Bovina A. F., Sokolov V. V., Mita E.
Заглавие : Magnetic resonance in FexMn1-xS single crystals
Коллективы : SB RAS-INTAS [06-1000013-9002]; JSPS KAKENHI [18540317]
Место публикации : J. Appl. Phys. - 2009. - Vol. 106, Is. 7. - Ст.73909. - ISSN 0021-8979, DOI 10.1063/1.3234402
Примечания : Cited References: 11. - This study was supported by the SB RAS-INTAS (Grant No. 06-1000013-9002) and the JSPS KAKENHI (Grant No. 18540317).
Ключевые слова (''Своб.индексиров.''): experimental studies--ferromagnetic particles--first-order--iron nanoparticles--manganese sulfide--mean diameter--randomly distributed--resonance spectrum--s-matrix--superparamagnetics--computer simulation--manganese--manganese compounds--resonance--superparamagnetism--single crystals
Аннотация: The results of the experimental study and computer simulation of the resonance spectra of a single crystal of the iron-manganese sulfide FexMn1-xS (0 = 6.19 nm at T=250 K) and the axial first-order anisotropy constant (K-1 = 4.08 erg/cm(3) at T=250 K) of the ferromagnetic particles are determined. The volume fraction of the iron phase is estimated. (C) 2009 American Institute of Physics. [doi:10.1063/1.3234402]
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Khrustalev B. P., Balaev A. D., Sosnin V. M.
Заглавие : Superparamagnetism in Fe-SiO nanocluster films
Место публикации : Fiz. Tverd. Tela: MEZHDUNARODNAYA KNIGA, 1995. - Vol. 37, Is. 6. - P.1676-1686. - ISSN 0367-3294
Примечания : Cited References: 30
Предметные рубрики: ELECTRICAL-PROPERTIES
TEMPERATURE
WOS
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8.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Li O. A., Edelman I. S., Chun-Rong Lin, Hung-Yi Chen, Kai-Wun Wu, Ovchinnikov S. G.
Заглавие : The unusual size dependence of magnetic properties of nickel zinc ferrite nanoparticles synthesized by combustion method
Коллективы : Euro-Asian Symposium "Trends in MAGnetism", "Trends in MAGnetism", Euro-Asian Symposium, Институт физики им. Л.В. Киренского Сибирского отделения РАН
Место публикации : VI Euro-Asian Symposium "Trends in MAGnetism" (EASTMAG-2016): abstracts/ ed.: O. A. Maksimova, R. D. Ivantsov. - Krasnoyarsk: KIP RAS SB, 2016. - Ст.P9.5. - P.391. - ISBN 978-5-904603-06-9 (Шифр -478014040)
Ключевые слова (''Своб.индексиров.''): nickel zinc ferrite--ferrite nanoparticles --superparamagnetism
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9.

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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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Knyazev Yu. V., Balaev D. A., Kirillov V. L., Bayukov O. A., Mart'yanov O. N.
Заглавие : Mossbauer spectroscopy study of the superparamagnetism of ultrasmall ε-Fe2O3 nanoparticles
Коллективы : Russian Science Foundation [17-12-01111]
Место публикации : JETP Letters. - 2018. - Vol. 108, Is. 8. - P.527-531. - ISSN 0021-3640, DOI 10.1134/S0021364018200092. - ISSN 1090-6487(eISSN)
Примечания : Cited References: 22. - This work was supported by the Russian Science Foundation (project no. 17-12-01111).
Предметные рубрики: High-temperature
Particles
ε-Fe2O3
Phase
Model
Аннотация: The superparamagnetism of an ensemble of ϵ-Fe2O3 nanoparticles with a mean size of 3.9 nm dispersed in a xerogel SiO2 matrix is studied by the Mössbauer spectroscopy method. It is shown that most nanoparticles at room temperature are in the superparamagnetic (unblocked) state. As the temperature decreases, the progressive blocking of the magnetic moments of the particles occurs, which is manifested in the Mössbauer spectra as the transformation of the quadrupole doublet into a Zeeman sextet. The analysis of the relative intensity of the superparamagnetic (quadrupole doublet) and magnetically split (sextets) spectral components in the range of 4–300 K provides the particle size distribution, which is in agreement with the transmission electron microscopy data. The values of the effective magnetic anisotropy constants (Keff) are determined, and the contribution of surface anisotropy (KS) is estimated for particles of various sizes. It is shown that the quantity Keff is inversely proportional to the particle size, which indicates the significant contribution of the surface to the magnetic state of the ϵ-Fe2O3 nanoparticles with the size of several nanometers.
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