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1.


   
    Study of current-voltage characteristics of Bi-based high-temperature superconductors with fractal cluster structure / K. A. Shaykhutdinov [et al.] // Physica C. - 2006. - Vol. 435, Is. 1-2. - P. 19-22, DOI 10.1016/j.physc.2006.01.010. - Cited References: 18 . - ISSN 0921-4534
РУБ Physics, Applied
Рубрики:
NORMAL-PHASE
   VORTEX MOTION

   TRANSPORT

Кл.слова (ненормированные):
superconducting foam -- pinning -- critical current density -- fractal -- percolation -- cluster -- Cluster -- Critical current density -- Fractal -- Percolation -- Pinning -- Superconducting foam -- Bismuth -- Critical current density (superconductivity) -- Electric currents -- Electric potential -- Foams -- Percolation (solid state) -- Polycrystalline materials -- Cluster -- Fractal -- Pinning -- Superconducting foam -- Superconducting materials
Аннотация: We study the effect of the structure on critical currents and current-voltage characteristics (CVC's) of foamed bismuth-based polycrystalline high-temperature superconductors (HTSC). The fractal cluster structure of superconducting foams has been observed and the fractal dimension of boundaries between superconducting and normal clusters has been determined. Based on the magnetic and transport properties of the foamed polycrystalline superconductors, we have shown that the initial parts of CVC's of the superconducting foams are described well by the model that accounts the magnetic flux trapping in fractal clusters of a normal phase. (c) 2006 Elsevier B.V. All rights reserved.

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Держатели документа:
LV Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia
ИФ СО РАН
Kirensky Institute of Physics, 660036 Akademgorodok, Krasnoyarsk, Russian Federation
Ioffe Physical-Technical Institute, 194021 Polytechnicheskaya St., 26, St.-Petersburg, Russian Federation

Доп.точки доступа:
Shaykhutdinov, K. A.; Шайхутдинов, Кирилл Александрович; Balaev, D. A.; Балаев, Дмитрий Александрович; Gokhfeld, D. M.; Гохфельд, Денис Михайлович; Kuzmin, Y. I.; Popkov, S. I.; Попков, Сергей Иванович; Petrov, M. I.; Петров, Михаил Иванович; International Workshop on Weak Superconductivity(2005 ; Sept. ; 16-19 ; Bratislava, Slovakia)
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2.


    Sshalaev, V. M.
    Resonant light-scattering by fractal clusters / V. M. Sshalaev, R. Botet, R. Jullien // Phys. Rev. B. - 1991. - Vol. 44, Is. 22. - P. 12216-12225, DOI 10.1103/PhysRevB.44.12216. - Cited References: 19 . - ISSN 0163-1829
РУБ Physics, Condensed Matter
Рубрики:
AEROGELS
   OPTICS

Аннотация: A scale-invariant theory of resonant Rayleigh scattering by fractal clusters is developed. Our main result is that the scattering cross section is greatly enhanced, because of the presence of very high local fields, which are correlated and strongly fluctuating. Simulations dealing with two examples of fractal structures, namely, random walk and cluster-cluster aggregates, are presented. The numerical results confirm the theoretical predictions of the scaling behavior for both absorption and scattering, and allow us to obtain the corresponding exponents. In addition to the results for scattering, the large scale of the simulations of the present work provides a comprehensive confirmation and a substantial extension of a recent study by Markel, Muratov, Stockman, and George [Phys. Rev. B 43, 8183 (1991)].

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Держатели документа:
UNIV HEIDELBERG,INST PHYS,W-6900 HEIDELBERG,GERMANY
LV KIRENSKY PHYS INST,KRASNOYARSK,USSR
UNIV PARIS 11,PHYS SOLIDES LAB,F-91405 ORSAY,FRANCE
ИФ СО РАН

Доп.точки доступа:
Botet, R.; Jullien, R.
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3.


   
    Spectroscopic studies of fractal aggregates of silver nanospheres undergoing local restructuring / S. V. Karpov [et al.] // J. Chem. Phys. - 2006. - Vol. 125, Is. 11. - Ст. 111101, DOI 10.1063/1.2229202. - Cited References: 30 . - ISSN 0021-9606
РУБ Physics, Atomic, Molecular & Chemical
Рубрики:
ENHANCED RAMAN-SCATTERING
   SMALL-PARTICLE COMPOSITES

   OPTICAL-PROPERTIES

   DISORDERED CLUSTERS

   NONLINEAR OPTICS

   LOCALIZATION

   NANOPARTICLES

   EIGENMODES

   BOUNDS

Кл.слова (ненормированные):
Large-scale fractal geometry -- Nonlinear optical responses -- Restructuring -- Silver nanospheres -- Aggregates -- Colloids -- Electromagnetic fields -- Fractals -- Nonlinear optics -- Sampling -- Spectroscopic analysis -- Silver
Аннотация: We present an experimental spectroscopic study of large random colloidal aggregates of silver nanoparticles undergoing local restructuring. We argue that such well-known phenomena as strong fluctuation of local electromagnetic fields, appearance of "hot spots" and enhancement of nonlinear optical responses depend on the local structure on the scales of several nanosphere diameters, rather than the large-scale fractal geometry of the sample. (c) 2006 American Institute of Physics.

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
Krasnoyarsk State Tech Univ, Dept Phys & Engn, Krasnoyarsk 660028, Russia
Univ Penn, Dept Radiol, Philadelphia, PA 19104 USA
Univ Penn, Dept Bioengn, Philadelphia, PA 19104 USA
ИФ СО РАН
L. V. Kirensky Institute of Physics, Russian Academy of Sciences, Siberian Branch, Krasnoyarsk 660036, Russian Federation
Department of Physics and Engineering, Krasnoyarsk State Technical University, Krasnoyarsk 660028, Russian Federation
Departments of Radiology and Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, United States

Доп.точки доступа:
Karpov, S. V.; Карпов, Сергей Васильевич; Gerasimov, V. S.; Герасимов, Валерий Сергеевич; Isaev, I. L.; Исаев, Иван Леонидович; Markel, V. A.
}
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4.


    Shalaev, V. M.
    Small-particle composites .2. Nonlinear optical properties / V. M. Shalaev, E. Y. Poliakov, V. A. Markel // Phys. Rev. B. - 1996. - Vol. 53, Is. 5. - P. 2437-2449, DOI 10.1103/PhysRevB.53.2437. - Cited References: 45 . - ISSN 0163-1829
РУБ Physics, Condensed Matter
Рубрики:
FRACTAL CLUSTERS
   RAMAN-SCATTERING

   SUSCEPTIBILITY

   CONDUCTIVITY

   EXCITATIONS

   COLLOIDS

   LIGHT

Аннотация: Strong fluctuations of local fields may result in very large optical nonlinearities in small-particle composites. Enhancement associated with particle clustering is found for a number of optical processes, including four-wave mixing (FWM), third-harmonic generation (THG), Raman scattering, and nonlinear refraction and absorption in Kerr media. Field fluctuations and optical nonlinear susceptibilities are especially large in fractal clusters. The enhancement of optical processes is expressed in terms of the resonant linear absorption by collective dipolar eigenmodes in a cluster, and quality factors, q, of the modes (q much greater than 1). It is shown that the susceptibility of a composite material consisting of random small-particle clusters is proportional to q(3) for Raman scattering and the Kerr optical nonlinearity, and to q(4) and q(6) for THG and FWM, respectively. For all of these processes, a spectral dependence of the effective susceptibility is found. Broad-scale numerical simulations of the optical response in small-particle composites are performed to complement the theory. The simulations are in reasonable agreement with available experimental data.

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Держатели документа:
LV KIRENSKII INST PHYS,KRASNOYARSK 660036,RUSSIA
RUSSIAN ACAD SCI,INST AUTOMAT & ELECTROMETRY,NOVOSIBIRSK 630090,RUSSIA
ИФ СО РАН

Доп.точки доступа:
Poliakov, E. Y.; Markel, V. A.
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5.


   
    Processes in resonant domains of metal nanoparticle aggregates and optical nonlinearity of aggregates in pulsed laser fields / A. P. Gavrilyuk, S. V. Karpov // Appl. Phys. B-Lasers Opt. - 2009. - Vol. 97, Is. 1. - P163-173, DOI 10.1007/s00340-009-3592-y. - Cited Reference Count: 43. - Гранты: Authors are thankful to Prof. V. A. Markel ( University of Pennsylvania) for computation of multipole polarizability of silver nanoparticle bispheres, for the attention to this paper, fruitful discussions and great support. This research was supported by grants: 27.1 of the Presidium of RAS, 9.1 DPS RAS, 5 SB RAS, 3818.2008.3 and 6612.2006.3 of the President of RF ( SS RAS), DSP 2.1.1.1814, 05- 03- 32642 RFBR. - Финансирующая организация: [27.1 of the Presidium of RAS]; [9.1 DPS RAS]; [5 SB RAS]; [3818.2008.3]; [6612.2006.3] . - SEP. - ISSN 0946-2171
Рубрики:
SMALL-PARTICLE COMPOSITES
   FRACTAL CLUSTERS

   SELECTIVE PHOTOMODIFICATION

   ABSORPTION-COEFFICIENTS

   REFRACTIVE-INDEXES

   SILVER

   ENHANCEMENT

   RESPONSES

   GOLD

Кл.слова (ненормированные):
Metal nanoparticles -- Nanosecond pulsed laser -- Nonlinear refractive index -- Optical nonlinearity -- Physical effects -- Pulsed-laser field -- Resonant domain -- Silver nanoparticles -- Simple Physical Models -- Aggregates -- Laser excitation -- Nanoparticles -- Nonlinear optics -- Organic polymers -- Pulsed laser applications -- Refractive index -- Silver
Аннотация: Optical nonlinearities in aggregates of nanoparticles formed in silver hydrosols (SHs) are studied under pico- and nanosecond pulsed laser excitation. The dependence of the nonlinear refractive index n (2) on the degree of hydrosol aggregation is studied experimentally at the wavelength lambda=1.064 mu m. It is found that n (2) changes sign when the degree of hydrosol aggregation is increased. Various physical effects occurring in resonant domains of the aggregates are analyzed using a simple physical model of two bound silver nanoparticles. The theory takes into account thermal, elastic, electrostatic, and light-induced effects. Experimental results are discussed in the context of this theory.

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
Russian Acad Sci, Inst Computat Modeling, Krasnoyarsk 660036, Russia
Siberian Fed Univ, Krasnoyarsk 660028, Russia

Доп.точки доступа:
Gavrilyuk, A. P.; Гаврилюк, Анатолий Петрович; Karpov, S. V.; Карпов, Сергей Васильевич
}
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6.


   
    Numerical studies of second- and fourth-order correlation functions in cluster-cluster aggregates in application to optical scattering / V. A. Markel [et al.] // Phys. Rev. E. - 1997. - Vol. 55, Is. 6. - P. 7313-7333, DOI 10.1103/PhysRevE.55.7313. - Cited References: 21 . - ISSN 1063-651X
РУБ Physics, Fluids & Plasmas + Physics, Mathematical
Рубрики:
DIFFUSION-LIMITED AGGREGATION
   COLLOIDAL AGGREGATION

   FRACTAL CLUSTERS

   ANTICORRELATION

   SIMULATIONS

Аннотация: Two- and four-point density correlation functions p(2)(r) and p(4)(r) are studied numerically and theoretically in computer-generated three-dimensional lattice cluster-cluster aggregates (CCA) with the number of particles N up to 20 000 in application to the light scattering problem. The ''pure'' aggregation algorithm is used, where subclusters of all possible sizes are allowed to collide. We find that large CCA clusters demonstrate pronounced multiscaling. In particular, the fractal dimension determined from the slope of p(2)(r) at small distances differs from that found from the dependence of the radius of gyration on the number of monomers (according to our data, 1.80 and 1.94, respectively). We also consider different functional forms for p(2) and their general properties and applicability. We find that the best fit to the numerical data is provided by the generalized exponential cutoff function with coefficients depending on N. The latter dependence is a manifestation of multiscaling. We propose some theoretical approaches for calculating p(4)(r), assuming p(2)(r) is known. In particular, we find the small-r asymptote for the p(4)(r) and verify it numerically. In addition, we find that p(4)(r) cannot be represented by a scaling dependence with a cutoff function, like p(2)(r) Instead, p(4)(r) is given by an expansion in terms of integer powers of r(2D-3), where D is the fractal dimension (approximate to 1.8 for CCA clusters).

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Держатели документа:
UNIV WISCONSIN,DEPT CHEM,OFF CHANCELLOR,STEVENS POINT,WI 54481
UNIV WISCONSIN,DEPT PHYS & ASTRON,STEVENS POINT,WI 54481
RUSSIAN ACAD SCI,INST AUTOMAT & ELECTROMETRY,NOVOSIBIRSK 630090,RUSSIA
RUSSIAN ACAD SCI,SIBERIAN BRANCH,LV KIRENSKY PHYS INST,KRASNOYARSK 660036,RUSSIA
ИФ СО РАН

Доп.точки доступа:
Markel, V. A.; Shalaev, V. M.; Poliakov, E. Y.; George, T. F.
}
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7.


   
    Nonlinear optics of metallic fractal clusters / A. V. Butenko [et al.] // Izvestiya Akademii Nauk SSSR Seriya Fizicheskaya. - 1989. - Vol. 53, Is. 6. - P. 1195-1201. - Cited References: 13 . - ISSN 0367-6765
РУБ Physics, Multidisciplinary


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Держатели документа:
LV KIRENSKII PHYS INST,KRASNOYARSK,USSR
ИФ СО РАН
Доп.точки доступа:
Butenko, A. V.; Danilova, Y. E.; Ishikaev, S. M.; Karpov, S. V.; Карпов, Сергей Васильевич; Popov, A. K.; Попов, Александр Кузьмич; Rautian, S. G.; Safonov, V. P.; Slabko, V. V.; Слабко, Виталий Васильевич; Crubakov, P. A.; Shalaev, V. M.; Shtokman, M. I.
}
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8.


    Myagkov, V. G.
    Fractal clusters and self-propagating high-temperature synthesis in thin Al/Ge films / V. G. Myagkov, L. E. Bykova // JETP Letters. - 1998. - Vol. 67, Is. 5. - P. 334-338, DOI 10.1134/1.567669. - Cited References: 14 . - ISSN 0021-3640
РУБ Physics, Multidisciplinary
Рубрики:
DENSE BRANCHING MORPHOLOGY
   SINGLE-CRYSTAL GROWTH

   AL-GE

   PHASE-SEPARATION

Аннотация: Fractal clusters in amorphous thin films are examples of growth models. The main models are the Witten-Sander model and its modifications. It is believed that fractal patterns are formed in the course of the crystallization of an amorphous phase. It is shown that self-propagating high-temperature synthesis can be initiated in an Al/Ge film system and fractal patterns are formed in the reaction products. It is conjectured that the transition of an amorphous phase to a crystalline phase does not play a substantial role in the appearance of such patterns, while the formation of fractal clusters is determined by self-propagating high-temperature synthesis. (C) 1998 American Institute of Physics. [S0021-3640(98)00605-7].

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Держатели документа:
Russian Acad Sci, Siberian Branch, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
ИФ СО РАН
L. V. Kirenskii Institute of Physics, Siberian Branch, Russian Academy of Sciences, 660036 Krasnoyarsk, Russian Federation

Доп.точки доступа:
Bykova, L. E.; Быкова, Людмила Евгеньевна; Мягков, Виктор Григорьевич
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9.


   
    Local anisotropy and giant enhancement of local electromagnetic fields in fractal aggregates of metal nanoparticles / S. V. Karpov [et al.] // Phys. Rev. B. - 2005. - Vol. 72, Is. 20. - Ст. 205425, DOI 10.1103/PhysRevB.72.205425. - Cited References: 56 . - ISSN 1098-0121
РУБ Physics, Condensed Matter
Рубрики:
SMALL-PARTICLE COMPOSITES
   DIFFUSION-LIMITED AGGREGATION

   OPTICAL-PROPERTIES

   SELECTIVE PHOTOMODIFICATION

   NUMERICAL-SIMULATION

   DISORDERED CLUSTERS

   ABSORPTION-SPECTRUM

   PARTICULATE MATTER

   NONLINEAR OPTICS

   LIGHT-SCATTERING

Аннотация: We have shown within quasistatic approximation that the giant fluctuations of a local electromagnetic field in random fractal aggregates of silver nanospheres are strongly correlated with a local anisotropy factor S which is defined in this paper. The latter is a purely geometrical parameter which characterizes the deviation of local environment of a given nanosphere in an aggregate from spherical symmetry. Therefore, it is possible to predict the sites with anomalously large local fields in an aggregate without explicitly solving the electromagnetic problem. We have also demonstrated that the average (over nanospheres) value of S does not depend noticeably on the fractal dimension D, except when D approaches the trivial limit D=3. In this case, as one can expect, the average local environment becomes spherically symmetrical and S approaches zero. This corresponds to the well-known fact that in trivial aggregates, fluctuations of local electromagnetic fields are much weaker than in fractal aggregates. Thus, we find that, within the quasistatics, the large-scale geometry does not have a significant impact on local electromagnetic responses in nanoaggregates in a wide range of fractal dimensions. However, this prediction is expected not to be correct in aggregates which are sufficiently large for the intermediate- and radiation-zone interaction of individual nanospheres to become important.

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
Krasnoyarsk State Tech Univ, Dept Phys & Engn, Krasnoyarsk 660028, Russia
Univ Penn, Dept Radiol, Philadelphia, PA 19104 USA
Univ Penn, Dept Bioengn, Philadelphia, PA 19104 USA
ИФ СО РАН
L. V. Kirensky Institute of Physics, Russian Academy of Sciences, Siberian Branch, Krasnoyarsk 660036, Russian Federation
Department of Physics and Engineering, Krasnoyarsk State Technical University, Krasnoyarsk 660028, Russian Federation
Departments of Radiology and Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, United States

Доп.точки доступа:
Karpov, S. V.; Карпов, Сергей Васильевич; Gerasimov, V. S.; Герасимов, Валерий Сергеевич; Isaev, I. L.; Исаев, Иван Леонидович; Markel, V. A.
}
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10.


    Komogortsev, S. V.
    Fractal Dimension Effect on the Magnetization Curves of Exchange-Coupled Clusters of Magnetic Nanoparticles / S. V. Komogortsev, R. S. Iskhakov, V. A. Fel'k // J. Exp. Theor. Phys. - 2019. - Vol. 128, Is. 5. - P. 754-760, DOI 10.1134/S1063776119040095. - Cited References: 54. - This work was supported by Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Region Science and Technology Support Fund under the research project no. 18-42-240006. . - ISSN 1063-7761. - ISSN 1090-6509
Рубрики:
THIN-FILMS
   COERCIVE FORCE

   NANOCRYSTALLINE

   SATURATION

   FERROMAGNETS

Аннотация: The effect of the fractal dimension of exchange-coupled clusters of magnetic nanoparticles on their magnetization curves is predicted by scaling estimates. These predictions form the basis for the experimental technique used for determining the fractal dimension of nanoparticle clusters from the magnetization curves. We estimate the reliability of determining the dimension by such methods with the help of micromagnetic simulation. It is shown that the effective dimension of magnetic correlation volumes, which is determined from analysis of the magnetization approaching saturation, is in conformity with the dimension of fractal clusters determined from analysis of their morphology. The dimension estimated from analysis of the coercive field on the particle size in a physically natural situation of the dipole-dipole interaction between nanoparticles provides estimates of the cluster dimension, which strongly differs from estimates obtained from analysis of their morphology.

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Публикация на русском языке Комогорцев, Сергей Викторович. Влияние фрактальной размерности на кривую намагничивания обменно-связанного кластера магнитных наночастиц [Текст] / С. В. Комогорцев, Р. С. Исхаков, В. А. Фельк // Журн. эксперимент. и теор. физ. - 2019. - Т. 155 Вып. 5. - С. 886-893

Держатели документа:
Russian Acad Sci, Siberian Branch, Kirensky Inst Phys, Fed Res Ctr,Krasnoyarsk Sci Ctr, Krasnoyarsk 660036, Russia.
Reshetnev Siberian State Univ Sci & Technol, Krasnoyarsk 660049, Russia.

Доп.точки доступа:
Iskhakov, R. S.; Исхаков, Рауф Садыкович; Fel'k, V. A.; Комогорцев, Сергей Викторович; Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Region Science and Technology Support Fund [18-42-240006]
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