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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kliava J., Malakhovskii A. V., Edelman I. S., Potseluyko A. M., Petrakovskaja E. A., Melnikova S.V., Zarubina T. V., Petrovskii G., Bruckental Y., Yeshurun Y.
Заглавие : Unusual magnetic transitions and nature of magnetic resonance spectra in oxide glasses containing gadolinium
Место публикации : Phys. Rev. B: AMER PHYSICAL SOC, 2005. - Vol. 71, Is. 10. - Ст.104406. - ISSN 1098-0121, DOI 10.1103/PhysRevB.71.104406
Примечания : Cited References: 40
Предметные рубрики: ELECTRON-PARAMAGNETIC-RESONANCE
BORATE GLASSES
IONS
BEHAVIOR
GD3+
SPECTROSCOPY
SYSTEMS
GD-3+
FIELD
SHAPE
Ключевые слова (''Своб.индексиров.''): gadolinium--glass--lanthanide--oxide--anisotropy--article--chemical structure--concentration response--electron spin resonance--energy--magnetism--molecular physics--nanoparticle--phase transition--refraction index--temperature sensitivity
Аннотация: Magnetic susceptibility, electron paramagnetic resonance (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 the more heavily doped glasses and ascribed to clustering of Gd3+ ions. Two magnetic phase transitions at 55 and 12 K were detected and ascribed, respectively, to ferromagnetic and antiferromagnetic clusters containing Gd ions. The overall shape of the EPR spectra shows the presence of clustering at the higher Gd contents. At low temperatures the cluster-related resonance signal is altered in shape, indicating an onset of magnetic anisotropy field. This signal is convincingly fitted to superparamagnetic resonance arising from ferromagnetic nanoparticles. The clustering, depending on the Gd concentration, correlates with a significant shift to lower energies of the strong optical absorption band edge, ascribed to a charge transfer transition between Gd ions. A nonmonotonous change of refractive index with the increase of the Gd content indicates changes in the glass matrix and in Gd cluster structure.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mendez-Bermudez J. A., Luna-Acosta G. A., Seba P., Pichugin K. N.
Заглавие : Understanding quantum scattering properties in terms of purely classical dynamics: Two-dimensional open chaotic billiards
Место публикации : Phys. Rev. E: AMER PHYSICAL SOC, 2002. - Vol. 66, Is. 4. - Ст.46207. - ISSN 1539-3755, DOI 10.1103/PhysRevE.66.046207
Примечания : Cited References: 34
Предметные рубрики: BALLISTIC-TRANSPORT
POINCARE SECTIONS
CAVITIES
EIGENFUNCTIONS
LOCALIZATION
CHANNEL
Ключевые слова (''Своб.индексиров.''): chaos theory--electron tunneling--laser applications--nonlinear systems--probability--waveguide components--chaotic motion--microlasers--quantum scattering--scattering probability--quantum theory--article
Аннотация: We study classical and quantum scattering properties of particles in the ballistic regime in two-dimensional chaotic billiards that are models of electron- or micro-waveguides. To this end we construct the purely classical counterparts of the scattering probability (SP) matrix \S(n,m)\(2) and Husimi distributions specializing to the case of mixed chaotic motion (incomplete horseshoe). Comparison between classical and quantum quantities allows us to discover the purely classical dynamical origin of certain general as well as particular features that appear in the quantum description of the system. On the other hand, at certain values of energy the tunneling of the wave function into classically forbidden regions produces striking differences between the classical and quantum quantities. A potential application of this phenomenon in the field of microlasers is discussed briefly. We also see the manifestation of whispering gallery orbits as a self-similar structure in the transmission part of the classical SP matrix.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sorokin P.B., Kvashnin A.G., Kvashnin D.G., Filicheva J.A., Avramov P. V., Chernozatonskii L.A., Fedorov A. S.
Заглавие : Theoretical Study of Atomic Structure and Elastic Properties of Branched Silicon Nanowires
Место публикации : ACS Nano. - 2010. - Vol. 4, Is. 5. - P.2784-2790. - MAY. - ISSN 1936-0851, DOI 10.1021/nn9018027
Примечания : Cited Reference Count: 28. - Гранты: P.B.S. acknowledges partial support by the National Science Foundation grant CMMI-0708096, NIRT. L.A.C. was supported by the Russian Academy of Sciences, program No. 21. P.V.A. and P.B.S. also acknowledge the collaborative RFBR-JSPS Grant No. 09-02-92107-Phi. All calculations have been performed on the Joint Supercomputer Center of the Russian Academy of Sciences. The geometry of all presented structures was visualized by ChemCraft software.Финансирующая организация: National Science Foundation [CMMI-0708096]; NIRT; Russian Academy of Sciences [21]; RFBR-JSPS [09-02-92107-Phi]
Предметные рубрики: ELECTRONIC-PROPERTIES
BUILDING-BLOCKS
NANOCRYSTALS
Ключевые слова (''Своб.индексиров.''): silicon nanowires--elastic properties--molecular mechanics--tersoff potential--elastic properties--molecular mechanics--silicon nanowires--tersoff potential--atomic structure--branch length--elastic properties--interatomic potential--silicon nanowires--tersoff potential--theoretical study--young modulus--carbon nanotubes--elasticity--molecular mechanics--nanowires--stiffness--crystal atomic structure--nanowire--silicon--article--chemical structure--chemistry--conformation--elasticity--mechanical stress--young modulus--elastic modulus--elasticity--models, molecular--molecular conformation--nanowires--silicon--stress, mechanical
Аннотация: The atomic structure and elastic properties of Y-shaped silicon nanowires of "fork"- and "bough"-types were theoretically studied, and effective Young moduli were calculated using Tersoff interatomic potential. The oscillation of fork Y-type branched nanowires with various branch lengths and diameters was studied. In the final stages of the bending, the formation of new bonds between different parts of the wires was observed. It was found that the stiffness of the nanowires is comparable with the stiffness of Y-shaped carbon nanotubes.
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Peng J. L., Bulcock S., Belobrov P. I., Bursill L. A.
Заглавие : Surface bonding states of nano-crystalline diamond balls
Место публикации : Int. J. Mod. Phys. B: WORLD SCIENTIFIC PUBL CO PTE LTD, 2001. - Vol. 15, Is. 31. - P4071-4085. - ISSN 0217-9792, DOI 10.1142/S0217979201007865
Примечания : Cited References: 20
Предметные рубрики: PLASMON RESPONSE
POWDER
SPECTROSCOPY
MICROSCOPY
SILICON
SI(111)
Ключевые слова (''Своб.индексиров.''): diamond--article--crystal structure--electron--energy transfer--nanoparticle--particulate matter--structure analysis--surface property--transmission electron microscopy
Аннотация: The rough surface of nano-crystalline diamond spheres induces surface electronic states which appear as a broadened pre-peak over approx. 15 eV at the C K-edge energy threshold for carbon in the parallel electron energy loss spectrum (PEELS). This appears to be at least partially due to 1s-pi* transitions, although typically the latter occupy a range of only 4 eV for the sp(2) edge of highly-oriented pyrollytic graphite (HOPG). No pi* electrons appear in the conduction band inside the diamond particles, where all electrons are sp(3) hybridized. PEELS data were also obtained from a chemical vapour deposited diamond film (CVDF) and gem-quality diamond for comparison with the spectra of nano-diamonds. The density of sp(2) and sp(3) states on the surface of diamond nano-crystals is calculated for simple structural models of the diamond balls, including some conjecture about surface structures. The results are used to interpret the sp(2)/sp(3) ratios measured from the PEELS spectra recorded as scans across the particles. Surface roughness at the atomic scale was also examined using high-resolution transmission electron microscopy (HRTEM) and electron nano-diffraction patterns were used to confirm the crystal structures.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Patrin G. S., Vas'kovskii V. O., Velikanov D. A., Svalov A. V., Panova M. A.
Заглавие : Spin-glass-like behavior of low field magnetisation in multilayer (Gd/Si/Co/Si)(n) films
Разночтения заглавия :авие SCOPUS: Spin-glass-like behavior of low field magnetisation in multilayer (Gd/Si/Co/Si)n films
Место публикации : Phys. Lett. A. - 2003. - Vol. 309, Is. 1-2. - P.155-159. - ISSN 0375-9601, DOI 10.1016/S0375-9601(03)00169-5
Примечания : Cited References: 13
Предметные рубрики: BIQUADRATIC EXCHANGE
Ключевые слова (''Своб.индексиров.''): cobalt--gadolinium--glass--silicon--silicon derivative--acceleration--article--film--magnetic field--magnetism--molecular dynamics--molecular interaction
Аннотация: The results of experimental investigations of magnetic properties of multilayer (Gd/Si/Co/Si)(n) films in low magnetic fields are represented. The spin-glass-like behavior of magnetization is found. The role of biquadratic exchange coupling in a forming of magnetic state of system is discussed. (C) 2003 Elsevier Science B.V. All rights reserved.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrakovskii G. A., Aleksandrov K. S., Aplesnin S. S., Roessli B., Semadeni F., Amato A., Baines C., Bartolome J., Evangelisti M.
Заглавие : Spin-glass state in CuGa2O4
Место публикации : Phys. Rev. B. - 2001. - Vol. 63, Is. 18. - Ст.184425. - ISSN 0163-1829, DOI 10.1103/PhysRevB.63.184425
Примечания : Cited References: 28
Предметные рубрики: TRANSITION
Ключевые слова (''Своб.индексиров.''): copper--gallium--glass--oxygen--acceleration--article--magnetism--measurement--molecular dynamics--phase transition
Аннотация: Magnetic susceptibility, magnetization, specific-heat, and positive muon spin relaxation (?SR) measurements have been used to characterize the magnetic ground state of the spinel compound CuGa2O4. We observe a spin-glass transition of the S = 1/2 Cu2+ spins below Tf = 2.5 K characterized by a cusp in the susceptibility curve which is suppressed when a magnetic field is applied. We show that the magnetization of CuGa2O4 depends on the magnetic history of the sample. Well below Tf, the muon signal resembles the dynamical Kubo-Toyabe expression reflecting that the spin freezing process in CuGa2O4 results in a Gaussian distribution of the magnetic moments. By means of Monte Carlo simulations, we obtain the relevant exchange integrals between the Cu2+ spins in this compound.
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Vtyurin A. N., Bulou A., Krylov A. S., Shmygol I. V., Aleksandrov K. S.
Заглавие : Raman scattering study of the upper phase transition in CsScF4
Место публикации : Journal of Raman Spectroscopy. - 2000. - Vol. 31, Is. 3. - P.151-155. - ISSN 0377-0486, DOI 10.1002/(SICI)1097-4555(200003)31:3151::AID-JRS5103.0.CO;2-T
Ключевые слова (''Своб.индексиров.''): article--crystal--heating--high temperature--melting point--neutron scattering--phase transition--photon--raman spectrometry--temperature dependence
Аннотация: Effects of the phase transition between the high-temperature tetragonal phases of the CsScF4 crystal were studied by Raman scattering. The appearance of new lines including a soft mode was observed below the phase transition point, in complete accordance with the new crystal symmetry. The behavior of the soft mode, which corresponds to in-phase rotations of ScF6 rigid groups around the z-axis (and out-of-phase within perovskite-like layers), resembles that observed earlier in RbAlF4, which suggests a similar mechanism of this transition in both crystals. Copyright (C) 2000 John Wiley and Sons, Ltd.
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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Nesterov A. I., de la Cruz F. A.
Заглавие : Magnetic monopoles with generalized quantization condition
Место публикации : Phys. Lett. A. - 2002. - Vol. 302, Is. 5-6. - P.253-260. - ISSN 0375-9601, DOI 10.1016/S0375-9601(02)01172-6
Примечания : Cited References: 33
Предметные рубрики: QUANTUM-MECHANICS
DIRAC MONOPOLE
3-COCYCLE
SPACE
Ключевые слова (''Своб.индексиров.''): monopole--nonunitary representations--nonassociativity--gauge loop--quasigroups--gauge loop--monopole--nonassociativity--nonunitary representations--quasigroups--article--calculation--magnetic field--mathematics--quantum mechanics--rotation--theory
Аннотация: Theory of pointlike magnetic monopole with an arbitrary magnetic charge is considered. It is shown that a proper description requires making use of nonunitary representations of the rotation group and the nonassociative generalization of the gauge group and fibre bundle theory. (C) 2002 Elsevier Science B.V. All rights reserved.
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ivchenko E. L., Voronov M. M., Erementchouk M. V., Deych L. I., Lisyansky A. A.
Заглавие : Multiple-quantum-well-based photonic crystals with simple and compound elementary supercells
Место публикации : Phys. Rev. B: AMERICAN PHYSICAL SOC, 2004. - Vol. 70, Is. 19. - Ст.195106. - ISSN 1098-0121, DOI 10.1103/PhysRevB.70.195106
Примечания : Cited References: 33
Предметные рубрики: EXCITON POLARITONS
DIELECTRIC MEDIUM
OPTICAL LATTICES
BRAGG STRUCTURES
BAND-STRUCTURES
PERIODIC-BRAGG
REFLECTION
ABSORPTION
SPECTRA
ARRAYS
Ключевые слова (''Своб.индексиров.''): article--crystal--crystal structure--elementary particle--light scattering--mathematical analysis
Аннотация: Exciton polaritons in one-dimensional photonic crystals based on multiple quantum well structures are investigated. The effects due to interplay between resonant interaction of light with quantum well excitons, and light scattering from well-barrier interface, are elucidated. Polariton dispersion equations and reflection spectra in structures with two wells in an elementary supercell of the periodic structure are studied. Several examples of different compound elementary supercells are considered. Special attention is paid to structures with the period or the distance between quantum wells satisfying the resonance Bragg condition. Such structures are characterized by a presence of a larger-than-usual polariton stop band. It is shown that in structures with a complex elementary supercell, the width of such a stop band can be significantly enhanced in comparison to that in simple structures.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zyryanov V. Ya., Myslivets S. A., Gunyakov V. A., Parshin A. M., Arkhipkin V. G., Shabanov V. F., Lee, Wei
Заглавие : Magnetic-field tunable defect modes in a photonic-crystal/liquid-crystal cell
Место публикации : Opt. Express. - 2010. - Vol. 18, Is. 2. - P.1283-1288. - JAN 18. - ISSN 1094-4087, DOI 10.1364/OE.18.001283
Примечания : Cited Reference Count: 15. - Гранты: This work was partially supported by the Russian Federal Grant No. 02.740.11.0220 and SB RAS Grant Nos. 5, 27.1 and 144. W. Lee gratefully acknowledges financial support from the National Science Council of the Republic of China (Taiwan) under Grant No. NSC 98-2923-M-033-001-MY3 dedicated to an internationally joint effort between Russia and Taiwan.Финансирующая организация: Russian Federal [02.740.11.0220]; SB RAS [5, 27.1, 144]; National Science Council of the Republic of China (Taiwan) [NSC 98-2923-M-033-001-MY3]
Предметные рубрики: NEMATIC LIQUID-CRYSTAL
BAND-GAP MATERIALS
SPONTANEOUS EMISSION
SPECTRUM
Ключевые слова (''Своб.индексиров.''): crystal defects--magnetic fields--photonic crystals--applied magnetic fields--crossed polarizers--crystal cells--defect mode--homeotropic--light transmission spectra--light wave--nematic director--optical cells--planar alignment--spectral shift--tunable defect--light transmission--article--artifact--chemistry--electromagnetic field--liquid crystal--materials--materials testing--radiation exposure--refractometry--artifacts--electromagnetic fields--liquid crystals--manufactured materials--materials testing--refractometry
Аннотация: Light transmission spectrum of a multilayer photonic crystal with a central liquid-crystal defect layer placed between crossed polarizers has been studied. Transmittance was varied due to the magnetically induced reorientation of the nematic director from homeotropic to planar alignment. Two notable effects were observed for this scheme: the spectral shift of defect modes corresponding to the extraordinary light wave and its superposition with the ordinary one. As a result, the optical cell allows controlling the intensity of interfering defect modes by applied magnetic field. (C) 2010 Optical Society of America
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Chukalina E. P., Kuritsin D. Y., Popova M. N., Bezmaternykh L. N., Kharlamova S. A., Temerov V. L.
Заглавие : Magnetic ordering of NdFe3(BO3)(4) studied by infrared absorption spectroscopy
Разночтения заглавия :авие SCOPUS: Magnetic ordering of NdFe3(BO3)4 studied by infrared absorption spectroscopy
Место публикации : Phys. Lett. A. - 2004. - Vol. 322, Is. 3-4. - P.239-243. - ISSN 0375-9601, DOI 10.1016/j.physleta.2003.12.062
Примечания : Cited References: 8
Предметные рубрики: CRYSTALS
Ключевые слова (''Своб.индексиров.''): ferroborates--fourier-transform spectroscopy--magnetic ordering--ferroborates--fourier-transform spectroscopy--magnetic ordering--iron--neodymium--absorption spectroscopy--article--electronics--infrared spectroscopy--magnetism--molecular interaction--molecular physics--temperature
Аннотация: We report the first measurements of the optical spectra of NdFe3(BO3)(4), a promising material for optoelectronics. Exchange splitting of Nd3+ spectral lines due to magnetic interactions in a magnetically ordered state was observed. The temperature dependences of the exchange splitting and of the linewidth point to the temperature T-c 33 +/- 1K of the magnetic ordering in both iron and neodymium. magnetic subsystems. 2004 Elsevier B.V. All rights reserved.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Men'shikov V. V., Ovchinnikov S. G., Rudenko V. V., Sudakov A. N., Tugarinov V. I., Vorotynov A. M.
Заглавие : Magnetic anisotropy quantitative estimation for the rhombohedral antiferromagnetic crystals containing S-state ions - art. no. 224405 (Retracted Article. see vol 72, art. no. 189901, 2005)
Разночтения заглавия :авие SCOPUS: Magnetic anisotropy quantitative estimation for the rhombohedral antiferromagnetic crystals containing S-state ions
Место публикации : Phys. Rev. B: AMER PHYSICAL SOC, 2005. - Vol. 71, Is. 22. - Ст.224405. - ISSN 1098-0121, DOI 10.1103/PhysRevB.71.224405
Примечания : Cited References: 33
Предметные рубрики: ELECTRON-PARAMAGNETIC-RES
EXCHANGE-COUPLED PAIRS
RESONANCE MEASUREMENTS
GARNETS
MN-2
Аннотация: The method to investigate "single-ion" exchange anisotropy (as predicted by the pair model) is treated by exploration of several isostructural diamagnetic crystals containing magnetic impurities. The electron paramagnetic resonance (EPR) spectra were observed for ferric borate isostructural crystals MBO(3): Fe(3+) (M = Ga, In, Lu, Sc). The experimental dependences of the spin-Hamiltonian axial parameters of the second-order D(S) and fourth-order (a-F)(cS) versus total pair spin S are presented. The contributions arising from the distortion of the parent crystal lattice MBO3 under magnetic dilution are estimated. The microscopic derived expressions for the "single-ion" contribution to the anisotropy are also presented. The present experimental data enable estimation of the "single- ion" exchange contribution for FeBO(3), MnCO(3), and alpha-Fe(2)O(3) crystals at T= 0 K. The quantitative estimations for EPR are in satisfactory agreement among themselves and with the experimental data.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kagan M.Yu., Efremov D. V., Mar'Enko M. S., Val'kov V. V.
Заглавие : Kohn-Luttinger effect and anomalous pairing in repulsive Fermi-systems at low density : Review Article
Место публикации : Физ. низких температур: Физико-технический институт низких температур им. Б.И. Веркина НАН Украины, 2012. - Т. 38, Вып. 9. - С.1102-1108. - ISSN 0132-6414
Примечания : Библиогр.: 59 назв. - We acknowledge helpful discussions with A. V. Chubukov, A. S. Alexandrov, V. V. Kabanov, K. I. Kugel, Yu. V. Kopaev, N. M. Plakida, and N. V. Prokof'ev. M. Yu. K's work was supported by RFBR Grant No 11-02-00741-a.
Ключевые слова (''Своб.индексиров.''): 3d and 2d hubbard model--fermi-gas model--superconductivity
Аннотация: In the large variety of models such as 3D and 2D Fermi-gas model with hard-core repulsion, 3D and 2D Hubbard model, and Shubin-Vonsovsky model we demonstrate the possibility of triplet p-wave pairing at low electron density. We show that the critical temperature of the p-wave pairing can be strongly increased in a spinpolarized case or in a two-band situation already at low density and reach experimentally observable values of (1-5) K. We also discuss briefly d-wave pairing and high-T c superconductivity with T c ∼ 100 K which arises in the extended Hubbard model and in the generalized t-J model close to half-filling.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kagan M. Y., Efremov D. V., Mar'enko M. S., Val'kov V. V.
Заглавие : Kohn-Luttinger effect and anomalous pairing in repulsive Fermi-systems at low density : Review Article
Место публикации : Low Temp. Phys.: American Institute of Physics, 2012. - Vol. 38, Is. 9. - P.874-879. - ISSN 1063-777X, DOI 10.1063/1.4752091
Примечания : Cited References: 59. - We acknowledge helpful discussions with A. V. Chubukov, A. S. Alexandrov, V. V. Kabanov, K. I. Kugel, Yu. V. Kopaev, N. M. Plakida, and N. V. Prokof'ev. M. Yu. K's work was supported by RFBR Grant No 11-02-00741-a.
Предметные рубрики: T-J MODEL
SUPERFLUID TRANSITION-TEMPERATURE
2-BAND HUBBARD-MODEL
LOW ELECTRON-DENSITY
FRACTIONAL-STATISTICS
PHASE-SEPARATION
SUPERCONDUCTIVITY
GAS
ENHANCEMENT
MECHANISM
Ключевые слова (''Своб.индексиров.''): d-wave superconductivity--electron density--electron spin polarisation--high-temperature superconductors--hubbard model--superconducting transition temperature--t-j model--two-dimensional electron gas
Аннотация: We demonstrate the possibility of triplet p-wave pairing at low electron density a large number of models such as 3D and 2D Fermi-gas models with hard-core repulsion, 3D and 2D Hubbard models, and the Shubin-Vonsovsky model. The critical temperature for p-wave pairing can be considerably higher in the spin-polarized case or even in a two-band situation at low density and can reach experimentally observable values of 1–5 K. We also discuss briefly the d-wave pairing and high-Tc superconductivity with Tc ∼ 100 K which arise in the extended Hubbard model and in the generalized t-Jmodel when close to half-filling.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Ignatchenko V. A., Felk V. A.
Заглавие : Exchange narrowing of magnetic resonance linewidths in inhomogeneous ferromagnets
Место публикации : Phys. Rev. B: AMERICAN PHYSICAL SOC, 2005. - Vol. 71, Is. 9. - Ст.94417. - ISSN 1098-0121, DOI 10.1103/PhysRevB.71.094417
Примечания : Cited References: 32
Предметные рубрики: AMORPHOUS FERROMAGNETS
RANDOM ANISOTROPY
NANOCRYSTALLINE
CRYSTALS
ALLOYS
Ключевые слова (''Своб.индексиров.''): ferromagnetic material--anisotropy--article--calculation--correlation analysis--crystal structure--magnetism--mathematical analysis--nanotechnology--nuclear magnetic resonance
Аннотация: The theory of exchange narrowing of ferromagnetic and spin-wave resonance linewidths in ferromagnets with the randomly inhomogeneous magnetic anisotropy is developed. The calculation is carried out by the method of averaged Green functions in the framework of the coherent potential approximation (CPA). One- and three-dimensional inhomogeneities with an arbitrary correlation wave number k(c) are considered (r(c)=k(c)(-1) is the correlation radius of the inhomogeneities). The method of the approximate solution of the CPA equation is proposed which has the quick convergence. Effects of exchange narrowing of the magnetic resonance lines and shifts of these lines are calculated in the whole region of the values of the correlation wave number k(c). The approximate analytical expressions for the linewidth of the FMR in the limiting cases of the small and large k(c) are obtained. Large narrowing of the FMR and spin-wave linewidths with the decrease of the correlation, radius of inhomogeneities is the substantiation. of the main advantage of nanocrystalline and amorphous materials over usual polycrystals when they are used at high frequency devices.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gluck M., Kolovsky A. R., Korsch H. J.
Заглавие : A quantum cable car for Wannier-Stark ladders
Место публикации : Phys. Lett. A. - 2000. - Vol. 276, Is. 1-4. - P.167-174. - ISSN 0375-9601, DOI 10.1016/S0375-9601(00)00656-3
Примечания : Cited References: 13
Предметные рубрики: DYNAMIC LOCALIZATION
BLOCH PARTICLE
AC FIELDS
DC
STATES
STATISTICS
LIFETIME
Ключевые слова (''Своб.индексиров.''): wannier-stark ladder--induced transitions--induced transitions--wannier-stark ladder--article--energy--oscillation--quantum mechanics--time--transport kinetics
Аннотация: This Letter studies the dynamics of transitions between the levels of a Wannier-Stark ladder induced by a resonant periodic driving. The analysis of the problem is done in terms of resonance quasienergy states, which take into account the metastable character of the Wannier-Stark states. It is shown that the periodic driving creates from a localized Wannier-Stark state an extended Bloch-like state with a spatial length varying in time as similar to t(1/2). Such a state can find applications in the field of atomic optics because it generates a coherent pulsed atomic beam. (C) 2000 Elsevier Science B.V. All rights reserved.
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17.

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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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Markel V. A., Pustovit V. N., Karpov S. V., Obuschenko A. V., Gerasimov V. S., Isaev I. L.
Заглавие : Electromagnetic density of states and absorption of radiation by aggregates of nanospheres with multipole interactions
Место публикации : Phys. Rev. B: AMER PHYSICAL SOC, 2004. - Vol. 70, Is. 5. - Ст.54202. - ISSN 1098-0121, DOI 10.1103/PhysRevB.70.054202
Примечания : Cited References: 81
Предметные рубрики: DISCRETE-DIPOLE APPROXIMATION
ENHANCED RAMAN-SCATTERING
METAL FRACTAL CLUSTERS
OPTICAL-PROPERTIES
SELECTIVE PHOTOMODIFICATION
DISORDERED CLUSTERS
NUMERICAL-SIMULATION
SPECTRAL DEPENDENCE
PARTICULATE MATTER
LIGHT-SCATTERING
Ключевые слова (''Своб.индексиров.''): carbon--iron--palladium--silver--article--dipole--electromagnetic field--geometry--mathematical analysis--molecular interaction--nanoparticle--radiation absorption
Аннотация: We calculate the quasistatic electromagnetic density of states for aggregates of touching spheres, in particular, linear chains and computer-generated random fractal aggregates. Multipole moments with orders of up to L=64 are taken into account for random aggregates with the number of particles of up to N=100 and up to L=8000 for linear chains. Extensive comparisons with the dipole approximation and geometrical cluster renormalization method are performed. Extinction spectra are calculated for several metals and black carbon. Long wavelength electromagnetic properties of fractal aggregates are considered in details.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volkov N. V., Eremin E. V., Sablina K. A., Sapronova N. V.
Заглавие : Dielectric properties of a mixed-valence Pb3Mn7O15 manganese oxide
Коллективы :
Разночтения заглавия :авие SCOPUS: Dielectric properties of a mixed-valence Pb3Mn7O 15 manganese oxide
Место публикации : J. Phys.: Condens. Matter: IOP PUBLISHING LTD, 2010. - Vol. 22, Is. 37. - Ст.375901. - ISSN 0953-8984, DOI 10.1088/0953-8984/22/37/375901
Примечания : Cited References: 14. - This study was supported by the Russian Foundation for Basic Research 'Siberia', project No. 09-02-98003, and the Siberian Branch of the Russian Academy of Sciences, integration project No. 101.
Ключевые слова (''Своб.индексиров.''): cation--lead--manganese derivative--oxide--article--chemical model--chemistry--crystallization--electric conductivity--electronics--methodology--temperature--cations--crystallization--electric conductivity--electronics--lead--manganese compounds--models, chemical--oxides--temperature--ac electric field--analysis of resistivity--carrier hopping--charge ordering--complex dielectric constant--crystal site--debye models--dielectric constants--dielectric spectra--frequency windows--lattice sites--low frequency--manganese ions--mixed valence--mixed valence state--relaxation behaviors--temperature range--electric fields--manganese--manganese oxide--permittivity--single crystals--crystal symmetry
Аннотация: We investigated the low-frequency dielectric properties of a Pb3Mn7O15 single crystal with manganese ions in the mixed-valence state (Mn3+/Mn4+). Dielectric relaxation was found in the frequency window from 20 to 100 kHz in the temperature range 110-180 K. The dielectric spectra of the crystal were analyzed using a Debye model. Estimations made within the model and analysis of resistivity data suggest that the relaxation behavior of the dielectric constant is related to polaronic charge carrier hopping. Around 250 K, charge ordering occurs in the crystal when the Mn3+ and Mn4+ ions are arranged in a specific order among the crystal sites. With a decrease in temperature, an ac electric field can induce a charge hop between the equivalent lattice sites available, related to crystal symmetry. This hopping is equivalent to the reorientation of an electric dipole that yields Debye-type behavior of the complex dielectric constant. The observed anisotropy in the behavior of the dielectric properties and resistivity can be attributed to a pronounced two-dimensional character of the crystal structure.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aplesnin S. S., Ryabinkina L. I., Abramova G. M., Romanova O. B., Vorotynov A. M., Velikanov D. A., Kiselev N. I., Balaev A. D.
Заглавие : Conductivity, weak ferromagnetism, and charge instability in an alpha-MnS single crystal
Разночтения заглавия :авие SCOPUS: Conductivity, weak ferromagnetism, and charge instability in an α-MnS single crystal; авие SCOPUS: Conductivity, weak ferromagnetism, and charge instability in an ?-MnS single crystal
Место публикации : Phys. Rev. B: AMERICAN PHYSICAL SOC, 2005. - Vol. 71, Is. 12. - Ст.125204. - ISSN 1098-0121, DOI 10.1103/PhysRevB.71.125204; Phys. Rev. B Condens. Matter Mater. Phys. - 2005. - Vol. 71, Is. 12. - Ст.125204. - Вариант Sopus
Примечания : Cited References: 11
Предметные рубрики: MANGANITES
Ключевые слова (''Своб.индексиров.''): ferromagnetic material--manganese derivative--absorption spectroscopy--article--calculation--conductance--crystal--electron spin resonance--hybridization--magnetic field--magnetism--measurement--molecular interaction--temperature dependence--temperature measurement--ferromagnetic material--manganese derivative--absorption spectroscopy--article--calculation--conductance--crystal--electron spin resonance--hybridization--magnetic field--magnetism--measurement--molecular interaction--temperature dependence--temperature measurement
Аннотация: The temperature dependence of resistivity, magnetization, and electron-spin resonance of the α-MnS single crystal were measured in temperature range of 5 K T 550 K. Magnetization hysteresis in an applied magnetic field up to 0.7 T at T
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