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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Pankrats A. I., Petrakovskii G. A., Bezmaternykh L. N., Bayukov O. A.
Заглавие : Antiferromagnetic resonance and phase diagrams of gadolinium ferroborate GdFe3(BO3)(4)
Разночтения заглавия :авие SCOPUS: Antiferromagnetic resonance and phase diagrams of gadolinium ferroborate GdFe3(BO3)4
Место публикации : J. Exp. Theor. Phys.: AMER INST PHYSICS, 2004. - Vol. 99, Is. 4. - P766-775. - ISSN 1063-7761, DOI 10.1134/1.1826168
Примечания : Cited References: 16
Ключевые слова (''Своб.индексиров.''): anisotropy--antiferromagnetic materials--antiferromagnetism--phase diagrams--resonance--single crystals--antiferromagnetic resonance--antiferromagnets--crystal axis--transition fields--gadolinium compounds
Аннотация: Antiferromagnetic resonance in single crystals of rhombohedral gadolinium ferroborate GdFe3(BO3)(4) was studied. The frequency-field dependences of antiferromagnetic resonance over the frequency range 26-70 GHz and the temperature dependences of resonance parameters for magnetic fields oriented along the crystal axis and in the basal plane were determined. It was found that the iron subsystem, which can be treated as a two-sublattice antiferromagnet with anisotropy of the easy-plane type, experienced ordering at T = 38 K. At temperatures below 20 K, the gadolinium subsystem with the opposite anisotropy sign strongly influenced the anisotropic properties of the crystal. This resulted in a spontaneous spin-reorientation transition from the easy-plane to the easy-axis state at 10 K. Below 10 K, magnetic field-induced transitions between the states were observed. Experimental phase diagrams on the temperature-magnetic field plane were constructed for fields oriented along the crystal axis and in the basal plane. A simple model was used to calculate the critical transition fields. The results were in close agreement with the experimental values measured at T = 4.2 K for both field orientations. (C) 2004 MAIK "Nauka / Interperiodica".
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2.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Stolyar S. V., Bayukov O. A., Ladygina V. P., Ishchenko L. A., Iskhakov R. S.
Заглавие : Biogenic ferrihydrite nanoparticles doped with gadolinium
Коллективы : Euro-Asian Symposium "Trends in MAGnetism": Nanomagnetism
Место публикации : V Euro-Asian simposium "Trend in MAGnetism": Nanomagnetism: abstracts. - Vladivostok: FEFU, 2013. - С. 232. - ISBN 978-5-7444-3124-2
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3.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Kuzmenko A. M., Mukhin A. A., Ivanov V.Yu., Bezmaternykh L. N.
Заглавие : Coupled R and Fe magnetic excitations in RFe 3(BO 3) 4 multiferroics
Коллективы : Moscow International Symposium on Magnetism
Место публикации : Diffusion and Defect Data Pt.B: Solid State Phenomena. - 2012. - Vol. 190. - P.269-272. - ISBN 9783037854365, DOI 10.4028/www.scientific.net/SSP.190.269
Ключевые слова (''Своб.индексиров.''): magnetic resonance--rare-earth iron borates--terahertz spectroscopy--antiferromagnetics--coupled mode--exchange coupled--frequency ranges--g factors--iron borate--magnetic excitations--multiferroics--resonance mode--strong interaction--transmission spectrums--antiferromagnetism--electron transitions--gadolinium--ions--magnetic materials--magnetic permeability--magnetic resonance--terahertz spectroscopy--neodymium
Аннотация: Various resonance modes were observed in the transmission spectra of rare-earth iron borates RFe 3(BO 3) 4 (R = Nd 3+, Sm 3+, Gd 3+) at the frequency range 100-600 GHz, which were attributed to collective magnetic excitations in the exchange coupled Fe- and R-subsystems, i.e. antiferromagnetic (Fe) resonance and electron transitions in the R-ions. Strong interaction of the Fe and R oscillations was revealed and theoretically analyzed taking into account feature of the R-ion ground state. Intensities of the coupled modes (contributions to magnetic permeability) strongly depend on a difference of Fe and R ions g-factors that allows defining the sign of the latter. In particular, an appreciable intensity of exchange (Nd) modes in NdFe 3(BO 3) 4 is caused by g Nd?,|| < 0 whereas in GdFe 3(BO 3) 4 with gGd ? gFe ? 2 the exchange (Gd) modes were hided due to compensation of Fe and Gd contributions. In SmFe 3(BO 3) 4, despite a negligible Sm g-factor, the Sm modes were clear observed due to their excitation via coupling with the Fe-subsystem. В© (2012) Trans Tech Publications.
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Edelman I. S., Kliava J., Ivanova O. S., Ivantsov R. D., Velikanov D. A., Zaikovskii V., Petrakovskaja E. A., Zubavichus Y., Stepanov S.
Заглавие : Effect of gadolinium on magnetic circular dichroism and electron magnetic resonance of ε-Fe2O3 nanoparticles formed in borate glasses
Место публикации : J. Non-Cryst. Solids. - 2019. - Vol. 506. - P.68-79. - ISSN 00223093 (ISSN) , DOI 10.1016/j.jnoncrysol.2018.12.006
Примечания : Cited References: 81. - The work is supported by Russian Academy of Sciences in the frame of the Project № 0356-2017-0030.
Ключевые слова (''Своб.индексиров.''): iron oxides--ε-fe2o3--borate glasses--nanoparticles--magnetic circular dichroism--electron magnetic resonance
Аннотация: A remarkable characteristic of borate glasses is the ability of forming magnetic nanoparticles at low doping with transition element oxides. We have studied structure and magnetic properties of iron oxide nanoparticles formed in borate glasses, in particular, concentration and temperature dependences of magnetic circular dichroism (MCD) and electron magnetic resonance (EMR) spectra. A series of glasses of molar composition 22.5K2O-22.5Al2O3–55B2O3 doped with 1.5 mass % of Fe2O3 and different contents of Gd2O3 from 0.1 to 1.0 mass % was prepared using a conventional melt quenching technique and subjected to an additional thermal treatment. The whole set of results allows to identify the predominant magnetic phase in these glasses as ε-Fe2O3 nanoparticles, with a considerable part of iron ions substituted by gadolinium. Analysis and computer simulations of the EMR spectra allow separating the contribution of electron paramagnetic resonance of diluted iron ions and together with the temperature dependences of magnetization demonstrate a superparamagnetic character of the nanoparticle magnetism.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Stepin E. A., Sushko E. S., Vnukova N. G., Churilov G. N., Rogova A. V., Tomilin F. N., Kudryasheva N. S.
Заглавие : Effects of endohedral Gd-containing fullerenols with a different number of oxygen substituents on bacterial bioluminescence
Колич.характеристики :19 с
Место публикации : Int. J. Mol. Sci. - 2024. - Vol. 25, Is. 2. - Ст.708. - ISSN 16616596 (ISSN), DOI 10.3390/ijms25020708. - ISSN 14220067 (eISSN)
Примечания : Cited References: 102. - This research was funded by the State Assignment of the Ministry of Science and Higher Education of the Russian Federation, project No. 0287-2021-0020, and partly supported by the Russian Science Foundation No. 23-26-10018, Krasnoyarsk Regional Science Foundation
Аннотация: Gadolinium (Gd)-containing fullerenols are perspective agents for magnetic resonance imaging and cancer research. They combine the unique paramagnetic properties of Gd with solubility in water, low toxicity and antiradical activity of fullerenols. We compared the bioeffects of two Gd-containing fullerenols with a different number of oxygen groups—20 and 42: Gd@C82O20H14 and Gd@C82O42H32. The bioluminescent bacteria-based assay was applied to monitor the toxicity of fullerenols, bioluminescence was applied as a signal physiological parameter, and bacterial enzyme-based assay was used to evaluate the fullerenol effects on enzymatic intracellular processes. Chemiluminescence luminol assay was applied to monitor the content of reactive oxygen species (ROS) in bacterial and enzymatic media. It was shown that Gd@C82O42H32 and Gd@C82O20H14 inhibited bacterial bioluminescence at 10?1 and 10?2 gL?1, respectively, revealing a lower toxicity of Gd@C82O42H32. Low-concentration (10?3–10?1 gL?1) bacterial bioluminescence activation by Gd@C82O42H32 was observed, while this activation was not found under exposure to Gd@C82O20H14. Additional carboxyl groups in the structure of Gd@C82O42H32 were determined by infrared spectroscopy and confirmed by quantum chemical calculations. The groups were supposed to endow Gd@C82O42H32 with higher penetration ability through the cellular membrane, activation ability, lower toxicity, balancing of the ROS content in the bacterial suspensions, and lower aggregation in aqueous media.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Dudnik A. I., Vnukova N. G., Drokin N. A., Bondarev V. S., Shestakov N. P., Tomashevich Y. V., Churilov G. N.
Заглавие : Electrophysical properties of hydroxylated endohedral metallofullerene with gadolinium
Место публикации : J. Phys. Chem. Solids. - 2019. - Vol. 135. - Ст.109094. - ISSN 00223697 (ISSN) , DOI 10.1016/j.jpcs.2019.109094
Примечания : Cited References: 35. - The reported study was funded by RFBR according to the research project No 18-29-19003.
Аннотация: The paper presents the results of experimental measurements of constitutive and electrophysical properties in hydroxylated endohedral metallofullerene with gadolinium sample. We extracted endohedral metallofullerene from carbon condensate, synthesized in high-frequency arc discharge plasma. Later hydroxyl groups were added. Via methods of infrared and x-ray photoelectronic spectroscopy, it was established that the molecules of hydroxylated endohedral metallofullerene have the Gd@C82Ox(OH)y, x + y=(40–42) composition. The method of measuring the electrical impedance in the frequency range from 100 Hz to 100 MHz shows that the resulting hydroxylated fullerene is an ion conductor. The measured frequency dependences of the dielectric permittivity and conductivity of hydroxylated fullerene are explained based on the assumption of an inhomogeneous distribution of electric charges in the material volume. Dielectric-hysteresis loops in the frequency range of 25 Hz–1 MHz and temperature range of 80–300 K, and volt-ampere characteristics were measured. The obtained results imply the appearance of residual polarization induced by the electric field in hydroxylated fullerene. However, the constant dipole moment is absent. © 2019
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sushko E. S., Vnukova N. G., Churilov G. N., Kudryasheva N. S.
Заглавие : Endohedral Gd-containing fullerenol: Toxicity, antioxidant activity and regulation of reactive oxygen species in cellular and enzymatic systems
Место публикации : Int. J. Mol. Sci. - 2022. - Vol. 23, Is. 9. - Ст.5152. - ISSN 16616596 (ISSN), DOI 10.3390/ijms23095152
Примечания : Cited References: 117. - This research was funded by Russian Foundation for Basic Research, N18-29-19003; Russian Foundation for Basic Research, Krasnoyarsk Territory and Krasnoyarsk Regional Fund of Science, N20-44-243001; and partly supported by the Program of the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing, Fundamental Study 2020-2025 (Russia)
Аннотация: The Gd-containing metallofullerene derivatives are perspective magnetic resonance imaging contrast agents. We studied the bioeffects of a water-soluble fullerene derivative, gadolinium-endohedral fullerenol, with 40–42 oxygen groups (Gd@Fln). Bioluminescent cellular and enzymatic assays were applied to monitor toxicity and antioxidant activity of Gd@Fln in model solutions; bioluminescence was applied as a signaling physiological parameter. The Gd@Fln inhibited bioluminescence at high concentrations (2·10−1 gL−1), revealing lower toxicity as compared to the previously studied fullerenols. Efficient activation of bioluminescence (up to almost 100%) and consumption of reactive oxygen species (ROS) in bacterial suspension were observed under low-concentration exposure to Gd@Fln (10−3–2·10−1 gL−1). Antioxidant capability of Gd@Fln was studied under conditions of model oxidative stress (i.e., solutions of model organic and inorganic oxidizers); antioxidant coefficients of Gd@Fln were determined at different concentrations and times of exposure. Contents of ROS were evaluated and correlations with toxicity/antioxidant coefficients were determined. The bioeffects of Gd@Fln were explained by hydrophobic interactions, electron affinity, and disturbing of ROS balance in the bioluminescence systems. The results contribute to understanding the molecular mechanism of “hormetic” cellular responses. Advantages of the bioluminescence assays to compare bioeffects of fullerenols based on their structural characteristics were demonstrated.
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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kaminskii A. A., Butashin A. V., Aleksandrov K. S., Bezmaternykh L. N., Temerov V. L., Kravtsov N. V., Firsov V. V., Seo D. T., Hommerich U., Temple D., Braud A.
Заглавие : Gd3Ga5O12:Nd3+ crystals for a continuous-wave diode-pumped laser operating in 4F3/2 4I11/2 and 4F3/2 4I13/2 channels
Место публикации : Crystallogr. Rep. - 2002. - Vol. 47, Is. 2. - P.308-312. - ISSN 1063-7745, DOI 10.1134/1.1466508
Примечания : Cited References: 15
Предметные рубрики: GALLIUM GARNET
EMISSION
Ключевые слова (''Своб.индексиров.''): gadolinium--gallium--neodymium--article--concentration response--crystal--pump--spectroscopy--x ray--x ray topography
Аннотация: Garnet crystals of the composition Gd3Ga5O12:Nd3+ (concentration series CNd = 1-10 at. %) were grown from flux. In terms of spectroscopy, these crystals, unlike those grown from melts, form a medium with a single activator center. For the first time, continuous-wave lasing was excited by diode pumping with the use of Gd3Ga5O12:Nd3+ crystals at the wavelengths ?3 = 1.3315 and ?4 = 1.3370 ?m of the 4F3/2 4I13/2 channel and also the simultaneous generation at two wavelengths, ?1 = 1.0621 and ?2 = 1.0600 ?m, of the 4F3/2 4I11/2 channel. В© 2002 MAIK "Nauka/Interperiodica".
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kalashnikova A. M., Pavlov V. V., Pisarev R. V., Bezmaternykh L. N., Bayer M., Rasing T.
Заглавие : Linear and nonlinear optical spectroscopy of gadolinium iron borate GdFe3(BO3)(4)
Разночтения заглавия :авие SCOPUS: Linear and nonlinear optical spectroscopy of gadolinium iron borate GdFe3(BO3)4
Место публикации : JETP Letters. - 2004. - Vol. 80, Is. 5. - P.293-297. - ISSN 0021-3640, DOI 10.1134/1.1825108
Примечания : Cited References: 26
Предметные рубрики: ORTHOFERRITES
Аннотация: The optical spectra and the second-harmonic generation (SHG) are studied in a noncentrosymmetric GdFe3(BO3)(4) magnet. In the region of weak absorption (alpha similar to 20-400 cm(-1)) below similar to3 eV, three absorption bands are distinguished, which can be unambiguously assigned to forbidden electronic transitions from the ground (6)A(1) state of the Fe3+ ion to its excited states T-4(1) (similar to1.4 eV), T-4(2) (similar to2 eV), and (4)A(1), E-4 (similar to2.8 eV). Intense absorption begins in the region above 3 eV (alpha similar to 2-4 x 10(5) cm(-1)), where two bands at similar to4.0 and 4.8 eV are observed, which are caused by allowed electric dipole charge-transfer transitions. The spectral features of SHG in the 1.2-3.0-eV region are explained by a change in the SHG efficiency caused by a change in the phase mismatch. It is shown that in the weak absorption region, phase matching can be achieved for SHG. (C) 2004 MAIK "Nauka / Interperiodica".
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kliava J., Edelman I. S., Potseluyko A. M., Petrakovskaja E. A., Berger R., Bruckental I., Yeshurun Y., Malakhovskii A. V., Zarubina Y. V.
Заглавие : Magnetic and optical properties and electron paramagnetic resonance of gadolinium-containing oxide glasses
Место публикации : J. Phys.: Condens. Matter: IOP PUBLISHING LTD, 2003. - Vol. 15, Is. 40. - P6671-6681. - ISSN 0953-8984, DOI 10.1088/0953-8984/15/40/005
Примечания : Cited References: 30
Предметные рубрики: ABSORPTION-SPECTRA
FARADAY-ROTATION
SPIN-RESONANCE
IONS
GD3+
SPECTROSCOPY
BEHAVIOR
GD-3
Ключевые слова (''Своб.индексиров.''): doping (additives)--electronic structure--glass--lanthanum compounds--light absorption--magnetic susceptibility--oxides--paramagnetic resonance--positive ions--rate constants--substitution reactions--absorption band--gadolinium containing oxide glasses--positive weiss constants--gadolinium compounds
Аннотация: Magnetic susceptibility, electron paramagnetic resonance (EPR) and optical absorption 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 and ascribed to clustering of Gd3+ ions. Computer simulations of the EPR spectra show that the short-range ordering in the environment of the Gd3+ ions is well preserved. The relative distribution widths of the ligand coordinates are less than 2%. In the more heavily doped glasses the EPR spectra are superpositions of signals arising from isolated ions and ferromagnetic clusters. The increase of Gd3+ concentration is shown to change substantially the strong optical absorption edge while only small changes of f-f absorption band characteristics are observed. This difference is associated with the different effect of the Gd ion clustering on the mechanisms of the strong absorption in the ultraviolet region and the f-f absorption.
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