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1.


    OVCHINNIKOV, S. G.
    EFFECT OF SUBSTITUTIONAL IMPURITY SPECIES ON THE SUPPRESSION OF MAGNETIC-PROPERTIES OF WEAKLY DOPED COPPER OXIDES / S. G. OVCHINNIKOV // Fiz. Tverd. Tela. - 1994. - Vol. 36, Is. 5. - P. 1307-1310. - Cited References: 16 . - ISSN 0367-3294
РУБ Physics, Condensed Matter
Рубрики:
ELECTRONIC-STRUCTURE
   SUPERCONDUCTIVITY

   LA2CUO4

   EXCITATIONS

   SPECTRA


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2.


    Ovchinnikov, S. G.
    Modification of magnetic and superconducting properties of layered cuprates due to copper substitution for zinc and nickel / S. G. Ovchinnikov // Fiz. Tverd. Tela. - 1995. - Vol. 37, Is. 12. - P. 3645-3654. - Cited References: 28 . - ISSN 0367-3294
РУБ Physics, Condensed Matter
Рубрики:
ELECTRONIC-STRUCTURE
   LA2CUO4

   LA2-XSRXCUO4

   EXCITATIONS

   DENSITY

   PLANE

   NI


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3.


    Avramov, P. V.
    Effects of the intense electron correlations on the shape of x-ray CuK absorption spectra of La2-xSrxCuO4 / P. V. Avramov, S. G. Ovchinnikov // Zhurnal Eksperimentalnoi Teor. Fiz. - 1995. - Vol. 108, Is. 4. - P. 1479-1488. - Cited References: 28 . - ISSN 0044-4510
РУБ Physics, Multidisciplinary
Рубрики:
HIGH-TC SUPERCONDUCTIVITY
   EDGE STRUCTURE

   LA2CUO4

   SATELLITES

   ALPHA

   EXCITATIONS

   COPPER

   OXIDES

   STATE

   SHAKE


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Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Аврамов, Павел Вениаминович
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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.


    Ignatchenko, V. A.
    Wave spectrum of multilayers with finite thicknesses of interfaces / V. A. Ignatchenko, Y. I. Mankov, A. A. Maradudin // Phys. Rev. B. - 2000. - Vol. 62, Is. 3. - P. 2181-2184, DOI 10.1103/PhysRevB.62.2181. - Cited References: 24 . - ISSN 0163-1829
РУБ Physics, Condensed Matter
Рубрики:
SPIN
   EXCITATIONS

   MEDIA

Аннотация: To describe a multilayer structure with arbitrary thicknesses of the interfaces between layers, we introduce a model in which the dependence of a material parameter along the axis of such a superlattice is described by a Jacobian elliptic sine function. Depending on the value of the modulus kappa of the elliptic function, the model describes the limiting cases of multilayers with sharp interfaces (kappa=1, d/l=0, where d is the thickness of the interface, l is the period of the superlattice) and of sinusoidal superlattices (kappa=0, d/l=1/4), as Well as all intermediate situations. We investigate the wave spectrum in such a superlattice. The dependences of the widths of the gaps in the spectrum at the boundaries of ail odd Brillouin zones on the ratio d/l are found. It is shown that the thicknesses of the interfaces can be determined if the experimental value of the relation between the widths of the first gap Delta v(1) and any other gap Delta v(n) is known.

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Держатели документа:
LV Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA
ИФ СО РАН

Доп.точки доступа:
Mankov, Y. I.; Maradudin, A. A.; Игнатченко, Вальтер Алексеевич
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6.


    Aplesnin, S. S.
    Static and dynamic magnetic properties of coupled spin-1/2 antiferromagnetic chains / S. S. Aplesnin // J. Phys.: Condens. Matter. - 2000. - Vol. 12, Is. 37. - P. 8191-8207, DOI 10.1088/0953-8984/12/37/316. - Cited References: 21 . - ISSN 0953-8984
РУБ Physics, Condensed Matter
Рубрики:
ONE-DIMENSIONAL ANTIFERROMAGNETS
   SYSTEMS

   SUSCEPTIBILITY

   EXCITATIONS

   SR2CUO3

   CA2CUO3

   KCUF3

Кл.слова (ненормированные):
Computational methods -- Copper compounds -- Correlation methods -- Functions -- Magnetic field effects -- Magnetic properties -- Magnetization -- Monte Carlo methods -- Quantum theory -- Specific heat -- Thermal effects -- Excitation spectroscopy -- Interchain coupling -- Intrachain couplings -- Mean-field approximation -- Spin-spin correlation function -- Spinons -- Antiferromagnetic materials
Аннотация: Calculations of the thermodynamic quantities, and the spectra of spinons, triplet excitations, and two-particle spin-singlet (Delta S-z = 0, +/- 1) excitations for a weakly coupled antiferromagnetic S = 1/2 spin chain are made using a mean-field approximation for the interchain couplings (J(2)) by the quantum Monte Carlo method. The mass gaps in these excitation spectra are estimated as functions of the interchain coupling. The critical held H-c, and the temperatures at which the spinon and singlet gaps close (T-1 and T-2, respectively) are obtained. Some peculiarities of the staggered magnetization, the specific heat, and the spin-spin correlation function are found at T-1 = 0.9J(2), T-2 = 1.5J(2), H-c = 3.8J(2), as determined by linear function fitting for J(2)/J(1) < 0.15 The intrachain and interchain couplings, and the staggered magnetization for KCuF3, Sr2CuO3, and Ca2CuO3 are estimated, and mass gaps are predicted to exist in the spectra of the spinons and the singlet two-particle excitations.

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

Доп.точки доступа:
Аплеснин, Сергей Степанович
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7.


   
    Evolution of the band structure of quasiparticles with doping in copper oxides on the basis of a generalized tight-binding method / V. A. Gavrichkov [et al.] // J. Exp. Theor. Phys. - 2000. - Vol. 91, Is. 2. - P. 369-383, DOI 10.1134/1.1311997. - Cited References: 45 . - ISSN 1063-7761
РУБ Physics, Multidisciplinary
Рубрики:
T-J MODEL
   CUPRATE SUPERCONDUCTORS

   ELECTRONIC-STRUCTURE

   EXCITATIONS

   DEPENDENCE

   TEMPERATURE

   DERIVATION

   SR2CUO2CL2

   SPECTRUM

   DENSITY

Аннотация: Two methods for stabilizing the two-hole B-3(1g) state as the ground state instead of the Zhang-Rice singlet are determined on the basis of an orthogonal cellular basis for a realistic multiband pd model of a CuO2 layer and the dispersion relations for the valence band top in undoped and doped cases are calculated. In the undoped case, aside from the valence band, qualitatively corresponding to the experimental ARPES data for Sr2CuO2Cl2 and the results obtained on the basis of the t-t'-J model, the calculations give a zero-dispersion virtual level at the valence band top itself. Because of the zero amplitude of transitions forming the virtual level the response corresponding to it is absent in the spectral density function. In consequence, the experimental ARPES data do not reproduce its presence in this antiferromagnetic undoped dielectric. A calculation of the doped case showed that the virtual level transforms into an impurity-type band and acquires dispersion on account of the nonzero occupation number of the two-hole states and therefore should be detected in ARPES experiments as a high-energy peak in the spectral density. The computed dispersion dependence for the valence band top is identical to the dispersion obtained by the Monte Carlo method, and the ARPES data for optimally doped Bi2Sr2CaCu2O8 + delta samples. The data obtained also make it possible to explain the presence of an energy pseudogap at the symmetric X point of the Brillouin band of HTSC compounds. (C) 2000 MAIK "Nauka/Interperiodica".

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Публикация на русском языке Эволюция зонной структуры квазичастиц с допированием в оксидах меди в рамках обобщенного метода сильной связи [Текст] / В. А. Гавричков [и др.] // Журн. эксперим. и теор. физ. - 2000. - Т. 118 Вып. 2. - С. 422-437

Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Div, Krasnoyarsk 660036, Russia
ИФ СО РАН

Доп.точки доступа:
Gavrichkov, V. A.; Гавричков, Владимир Александрович; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Borisov, A. A.; Goryachev, E. G.
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8.


   
    Magnetic anisotropy of antiferromagnet (CH3)(4)NMnCl3 / A. M. Vorotynov [et al.] // Phys. Solid State. - 2000. - Vol. 42, Is. 7. - P. 1313-1316, DOI 10.1134/1.1131384. - Cited References: 14 . - ISSN 1063-7834
РУБ Physics, Condensed Matter
Рубрики:
EXCITATIONS
Аннотация: The parameters of the electron paramagnetic resonance (EPR) spectra of S ion pairs in diamagnetic crystals are analyzed. A relation between the spin Hamiltonian constants is established for solitary ions and pairs for (CH3)(4)NCdCl3:Mn2+ crystals. In contrast to solitary ions, an additional contribution (which is a linear function of the exchange field) to the "single-ion" spin Hamiltonian constants appears in the case of pairs. It is shown that anisotropic exchange mechanisms do not play a significant part in the formation of the axial constant of the spin Hamiltonian for this crystal. Some aspects of the method of studying "single-ion" anisotropy predicted by the two-ion model are developed with the help of an isostructural diamagnetic analog with impurity concentration of the paramagnetic ions of a magnetically concentrated substance sufficiently high for observing the EPR spectrum of the pairs. It is found that the microscopic quantities determined partially from the EPR spectra for pairs and solitary Mn2+ ions in (CH3)(4)NCdCl3 are in accord with the experimental value of the effective field for the (CH3)(4)NMnCl3 crystal anisotropy which can be described primarily by the dipole and "single-ion" mechanisms of the exchange origin. (C) 2000 MAIK "Nauka/Interperiodica".

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Div, Krasnoyarsk 660036, Russia
ИФ СО РАН

Доп.точки доступа:
Vorotynov, A. M.; Воротынов, Александр Михайлович; Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Rudenko, V. V.; Руденко, Валерий Васильевич; Sudakov, A. N.
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9.


    Aplesnin, S. S.
    Quantum Monte Carlo investigation of the magnetic properties of weakly interacting antiferromagnetic chains with an alternating exchange interaction with spin S=1/2 / S. S. Aplesnin // J. Exp. Theor. Phys. - 2000. - Vol. 90, Is. 1. - P. 194-201, DOI 10.1134/1.559075. - Cited References: 35 . - ISSN 1063-7761
РУБ Physics, Multidisciplinary
Рубрики:
PEIERLS COMPOUND CUGEO3
   MAGNON DISPERSION

   BI2CUO4

   EXCITATIONS

   RESONANCE

   SYSTEMS

   SCATTERING

   DYNAMICS

   NEUTRON

   PHASE

Аннотация: An approximation dependence of the spontaneous magnetic moment at a site, sigma/sigma(0) - 1 = 0.71(6)delta(2.5(2)), and the antiferromagnet-singlet state phase boundary, J(2)/J(1) = 0.52(3)delta, are determined by the quantum Monte Carlo method in the self-consistent sublattice molecular field approximation for weakly interacting (J(2)) antiferromagnetic chains with spin S = 1/2 and alternating exchange interaction (J(1) +/- delta). The Neel temperature and a number of critical temperatures which could be related with the filling energy of two singlets (Delta S-z = 0) and one triplet (Delta S-z= 1) spin bands, each of which is split by the sublattice field (h(x,y)not equal h(z)) into two subbands, are determined on the basis of the computed correlation radii of the two- and four-spin correlation function, the squared total spin (S-z)(2) with respect to the longitudinal components, the dimerization parameter, and the correlation functions between the nearest neighbors with respect to longitudinal and transverse spin components. On the basis of the Monte Carlo calculations, the critical temperatures and possible energy gaps at the band center are determined for the antiferromagnets CuWO4 and Bi2CuO4 and for the singlet compounds (VO)(2)P2O7 and CuGeO3 , agreeing satisfactorily with existing results, and new effects are also predicted. (C) 2000 MAIK "Nauka / Interperiodica".

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Держатели документа:
Russian Acad Sci, Siberian Div, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
ИФ СО РАН

Доп.точки доступа:
Аплеснин, Сергей Степанович
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10.


    Ignatchenko, V. A.
    Waves in a superlattice with arbitrary interlayer boundary thickness / V. A. Ignatchenko, O. N. Laletin // Phys. Solid State. - 2004. - Vol. 46, Is. 12. - P. 2292-2300, DOI 10.1134/1.1841396. - Cited References: 34 . - ISSN 1063-7834
РУБ Physics, Condensed Matter
Рубрики:
PERIODIC STRUCTURES
   RAYLEIGH-WAVES

   LAYERED MEDIUM

   ELASTIC-WAVES

   SPIN-WAVES

   SPECTRUM

   MEDIA

   PROPAGATION

   EXCITATIONS

   MULTILAYERS

Аннотация: The transmittance D(omega), reflectance R(omega), and dispersion omega(k) are investigated for waves of various nature propagating through a one-dimensional superlattice (multilayer structure) with arbitrary thickness of the interlayer boundary. The dependences of the band gap widths Deltaomega(m) and their positions in the wave spectrum of the superlattice on the interlayer boundary thickness d and the band number m are calculated. Calculations are performed in terms of the modified coupled-mode theory (MCMT) using the frequency dependence of R(omega), as well as in the framework of perturbation theory using the function omega(k), which made it possible to estimate the accuracy of the MCMT method; the MCMT method is found to have a high accuracy in calculating the band gap widths and a much lower accuracy in determining the gap positions. It is shown that the m dependence of Deltaomega(m) for electromagnetic (or elastic) waves is different from that for spin waves. Furthermore, the widths of the band gaps with m = 1 and 2 are practically independent of d, whereas the widths of all gaps for m 2 depend strongly on d. Experimental measurements of these dependences allow one to determine the superlattice interface thicknesses by using spectral methods. (C) 2004 MAIK "Nauka/Interperiodica".

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Держатели документа:
Russian Acad Sci, Siberian Div, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
Krasnoyarsk State Univ, Krasnoyarsk 660041, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk 660036, Russian Federation
Krasnoyarsk State University, Krasnoyarsk, 660041, Russian Federation

Доп.точки доступа:
Laletin, O. N.; Игнатченко, Вальтер Алексеевич
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