Библиотека института физики им. Л.В. Киренского СО РАН

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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Vorobyev S. A., Saikova S. V., Erenburg S. B., Trubina S. V., Ivanov Y. N., Maksimov N. G., Mikhlin Y. L.
Заглавие : A comparative study of the structure of copper and lead xanthates
Место публикации : J. Struct. Chem. - 2017. - Vol. 58, Is. 6. - P.1144-1151. - ISSN 00224766 (ISSN), DOI 10.1134/S0022476617060117
Примечания : Cited References: 38
Ключевые слова (''Своб.индексиров.''): copper xanthate--lead xanthate--dixanthogen--structure--xps--exafs--solid state nmr
Аннотация: XPS, PbL3 and CuK EXAFS, solid state NMR, and EPR techniques are used to study insoluble products formed in the interaction of aqueous solutions of lead(II) nitrate and copper (II) sulfate with potassium nbutylxanthate (KX). The XPS spectra of lead xanthates with the composition PbX2 are similar to those of KX, and interatomic distances of 0.279 nm suggest a nearly ionic character of Pb–S bonds. In copper xanthate precipitating together with dixanthogen (approximately 15 wt.%), the Cu(I)–S bond length is smaller (0.229 nm), and copper coordination number of 2.9 in a composite with dixanthogen increases to 3.3 after its removal by washing with acetone. The XPS spectra indicate the covalent character of the bond and non-equivalence of xanthate radicals. Solid state 1H and 13C NMR spectra as well as the actual absence of metal lines under the measurement conditions demonstrate strong disordering of the structure of xanthates, which is stronger for PbX2 and weakest in CuX after the removal of dixanthogen. EPR reveals sulfur-containing radicals and Cu2+ in CuX, however, their amounts are insignificant and decrease after the washing with acetone. The results of the work are significant for the understanding of the reactivity of xanthates, in particular, under the conditions of flotation of base metal ores.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrov M. I., Balaev D. A., Shaikhutdinov K. A., Aleksandrov K. S.
Заглавие : A comparative study of transport properties of composites HTSC+MgTiO3 and HTSC + NiTiO3. The effect of paramagnetic NiTiO3
Коллективы : International conference on materials and mechanisms of superconductivity high temperature superconductors
Место публикации : Physica C-Superconductivity and its Applications. - 2000. - Vol. 341-348, Pt. 3. - P.1863-1864. - ISSN 0921-4534, DOI 10.1016/S0921-4534(00)01217-X
Ключевые слова (''Своб.индексиров.''): composite materials--copper oxides--josephson junction devices--magnesium compounds--nickel compounds--paramagnetism--superconductivity--thermal effects--transport properties--yttrium compounds--abrikosov vortices flow--superconductor insulator superconductor junction--thermally activated phase slippage--high temperature superconductors
Аннотация: Bulk composites Y3/4Lu1/4Ba2Cu3O7+NiTiO3 and Y3/4Lu1/4Ba2Cu3O7+MgTiO3 with insulator volume content 7.5% and 15% modelling a network of Superconductor-Insulator-Superconductor (S-I-S) junctions have been prepared. The ?(T) dependences of composites HTSC+MgTiO3 are described well by the mechanism of Thermally Activated Phase Slippage (TAPS). The anomalous behavior of resistivity ?(T) of HTSC+NiTiO3 composites manifesting as a kink on ?(T) curves at some temperature Tm have been observed. In the temperature range Tm < T < TC the dissipation is Ohmic while below Tm the CVCs are strongly non-linear. This peculiarity is interpreted as arisen owing to Abrikosov vortices flow.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Lykhin A. O., Novikova G. V., Kuzubov A. A., Staloverova N. A., Sarmatova N. I., Varganov S. A., Krasnov P. O.
Заглавие : A complex of ceftriaxone with Pb(II): synthesis, characterization, and antibacterial activity study
Коллективы : RFBR [14-03-31, 170 MOJI_a]
Место публикации : J. Coord. Chem.: Taylor & Francis, 2014. - Vol. 67, Is. 16. - З2783-2794. - ISSN 0095-8972, DOI 10.1080/00958972.2014.938065. - ISSN 1029-0389
Примечания : Cited References: 48. - The reported study was supported by RFBR, research project No. 14-03-31, 170 MOJI_a and Krasnoyarsk regional fund for supporting scientific and technological activities. We thank the Center for Equipment Joint Use of the Siberian Federal University. We are grateful to the HPC Research Departments of Siberian Federal University and Moscow University Supercomputing Center (SKIF MSU "Chebyshev") for the access to the high-performance computer clusters.
Предметные рубрики: BETA-LACTAM ANTIBIOTICS
TERNARY COMPLEX
METAL-COMPLEXES
BASIS-SETS
3 DECADES
RESISTANCE
COPPER(II)
CEPHALOSPORINS
EVOLUTION
1ST-ROW
Ключевые слова (''Своб.индексиров.''): ceftriaxone lead(ii) complex--dft--ir spectroscopy--tga--antibacterial screening
Аннотация: A Pb(II) complex with ceftriaxone (H2Ceftria) antibiotic was synthesized by reaction of ceftriaxone disodium salt (hemi)heptahydrate with lead nitrate in water–ethanol medium. The complex was characterized on the basis of complexometric titration, spectrophotometric and thermogravimetric analyses, capillary electrophoresis, IR, Raman and UV–vis spectroscopies, and density functional theory calculations. Pb(II) is five-coordinate with distorted square pyramidal geometry. The coordination of Ceftria2− to Pb(II) occurs through N and O of the triazine, lactam carbonyl, carboxylate, and amine groups. The antibacterial activity study showed that Klebsiella pneumoniae is resistant to [Pb(Ceftria)]·3H2O. The antibacterial activity of [Pb(Ceftria)]·3H2O against Staphylococcus aureus is reduced compared with ceftriaxone. In contrast, the antibacterial activity of [Pb(Ceftria)]·3H2O against Escherichia coli is 28% higher than that of ceftriaxone antibiotic.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Boehm M., Roessli B., Schefer J., Ouladdiaf B., Amato A., Baines C., Staub U., Petrakovskii G. A.
Заглавие : A neutron scattering and mu SR investigation of the magnetic phase transitions of CuB2O4
Место публикации : Physica B: ELSEVIER SCIENCE BV, 2002. - Vol. 318: 6th Patras-University Euroconference on Properties of Condensed Matter Probed with X-Ray Scattering-Electron Correlations and Magnetism (SEP 21-25, 2001, PATRAS, GREECE), Is. 4. - P277-281. - ISSN 0921-4526, DOI 10.1016/S0921-4526(02)00788-3
Примечания : Cited References: 8
Предметные рубрики: COPPER METABORATE
Ключевые слова (''Своб.индексиров.''): magnetic soliton lattice--dzyaloshinskii-moriya interaction--neutron diffraction--mu sr
Аннотация: We have investigated the magnetic ground state in CuB2O4, copper metaborate, by means of neutron diffraction and muSR measurements. At T-N = 21 K CuB2O4 undergoes a second-order phase transition from a paramagnetic to an antiferromagnetic commensurate state followed by a second transition at T* = 10 K where the two magnetic sublattices form a soliton lattice, as reported earlier. We give a detailed analysis of the magnetic structure in the commensurate phase which is found to be different from the one published recently. New experimental results are presented which show the existence of a third transition below T approximate to 1.8 K. The magnetic structure remains incommensurate at very low temperatures, but a re-distribution of the magnetic intensities is observed in the neutron diffraction data set which suggests that the phases between the Cu2+ spins are changed. (C) 2002 Elsevier Science B.V. All rights reserved.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Vorob’ev S. A., Burdakova E. A., Sarycheva A. A., Volochaev M. N., Karacharov A. A., Likhatskii M. N., Mikhlin Y. L.
Заглавие : Analysis of function of copper sulfide nanoparticles as sphalerite flotation activator
Место публикации : J. Min. Sci. - 2021. - Vol. 57, Is. 1. - P.144-153. - ISSN 10627391 (ISSN), DOI 10.1134/S1062739121010154
Примечания : Cited References: 22. - This study was supported by the Russian Science Foundation, project no. 18-17-00135
Аннотация: The authors compare the effect exerted by copper ions and sulphide copper nanoparticles on flotation of Gorevka deposit sphalerite using potassium n-butyl xanthate and in reagent-less regime. Covelline-like colloid particles 4–8 nm in size, obtained in interaction of copper (II) and sulfide ions in aqueous solutions, are characterized using the methods of dynamic light scattering, electron microscopy and diffraction. Sphalerite surface after reaction with copper ions and CuS dispersoid solutions are described by zeta-potential measurements and X-ray photoelectron spectroscopy. It is found that sphalerite flotation after activation with nanoparticles is lower than with copper ion solutions of the same concentrations, and improves with increasing duration of activation and flotation processes. The mechanism of CuS nanoparticles consists in creation of active centers for the collector to attach to, which intensifies the hydrophobic behavior and adsorption of the collector. Moreover, CuS nanoparticles promote formation of a special microrelief of the solid–liquid interface, which ensures rupture of liquid film and attachment of sphalerite particles to air bubbles when they collide.
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Вид документа : Статья из сборника (выпуск продолж. издания)
Шифр издания :
Автор(ы) : Chepkasov I. V., Popov Z. I.
Заглавие : Analysis of thermal effects on copper nanoparticles synthesized from the gas phase
Коллективы : International scientific conference on radiation-thermal effects and processes in inorganic materials , International Scientific Conference on Radiation-Thermal Effects and Processes in Inorganic Materials (Nov 03-08, 2014; Tomsk, Russia)
Место публикации : IOP Conf. Ser.: Mater. Sci. Eng. - 2015. - Vol. 81. - Ст.012033. - , DOI 10.1088/1757-899X/81/1/012033
Примечания : Cited References:14
Предметные рубрики: DEVICES
FILMS
Аннотация: Molecular dynamics method using the tight-binding potential to carry out simulation of ultrafast heating of the synthesized particles from the gas phase to a temperature T= 600K and T= 900K, at which the particles were kept about 10 ns. As a result of the simulation revealed that the method of ultrafast heating the particles to high temperatures virtually eliminates the possibility of a clusters of defective education, but as a result of the heat treatment, the some of investigated particles can disconnect (burst) into smaller clusters.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrov M. I., Gokhfeld D. M., Balaev D. A., Shaihutdinov K. A., Kummel R.
Заглавие : Andreev reflections and experimental current-voltage characteristics of break junctions of polycrystalline HTSC
Место публикации : Physica C: ELSEVIER SCIENCE BV, 2004. - Vol. 408: 7th International Conference on Materials and Mechanisms of Superconductive and High Temperature Superconductors (MAY 25-30, 2003, Rio de Janeiro, BRAZIL). - P620-622. - ISSN 0921-4534, DOI 10.1016/j.physc.2004.03.085
Примечания : Cited References: 3
Ключевые слова (''Своб.индексиров.''): andreev reflections--break junction--current-voltage characteristics--andreev reflections--break junction--current-voltage characteristics--andreev reflections--break junctions--elastic scattering--lattice defects--negative differential resistance--electric fields--heuristic methods--hysteresis--microcracks--polycrystalline materials--probability density function--quasicrystals--superconducting materials--yttrium barium copper oxides--current voltage characteristics
Аннотация: The temperature evolution of current-voltage characteristics (CVCs) of break junctions made from polycrystalline Y0.75Lu0.25Ba2Cu3O7 and La1.85Sr0.15CuO4 is investigated. The experimental CVCs have hysteretic features that reflect a part of a curve with negative differential resistance. The temperature evolution of the CVCs is discussed within the framework of the Kummel-Gunsenheimer-Nicolsky theory for superconductor/normal-metal/superconductor junctions considering multiple Andreev reflections. It is shown that the shape of the CVCs of break junctions is determined by the ratio of the number of "short" and "long" intergrain normal regions in the polycrystalline HTSC under investigation. (C) 2004 Elsevier B.V. All rights reserved.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Boldyrev K. N., Pisarev R. V., Bezmaternykh L. N., Popova M. N.
Заглавие : Antiferromagnetic dichroism in a complex multisublattice magnetoelectric CuB2O4
Коллективы : Russian Academy of Sciences under the Programs for Basic Research; Russian Federation [MK-3521.2015.2], Russian Foundation for Basic Research [15-32-20613, 15-02-04222], Ministry of Education and Science of the Russian Federation [14.B25.0031.25]
Место публикации : Phys. Rev. Lett.: American Physical Society, 2015. - Vol. 114, Is. 24. - Ст.247210. - ISSN 0031, DOI 10.1103/PhysRevLett.114.247210. - ISSN 10797114(eISSN)
Примечания : Cited References:40. - This study was supported by the Russian Academy of Sciences under the Programs for Basic Research, by the President of the Russian Federation (Grant No. MK-3521.2015.2, K. N. B.), by the Russian Foundation for Basic Research (Grants No. 15-32-20613, K. N. B., and No. 15-02-04222, R. V. P.), and by the Ministry of Education and Science of the Russian Federation (Grant No. 14.B25.0031.25, R. V. P.).
Предметные рубрики: MAGNETIC SOLITON LATTICE
COPPER METABORATE
GYROTROPIC BIREFRINGENCE
SPECTROSCOPY
EXCITATIONS
TRANSITIONS
CRYSTALS
Cr2O3
FIELD
Аннотация: Magnetic control of the crystal chirality was announced by Saito et al. [Phys. Rev. Lett. 101, (2008)] on the ground of experiments in CuB2O4. This claim has raised a sharp dispute in the literature because it seemed to contradict the fundamental symmetry principles. We settle this dispute on the basis of a high-resolution optical spectroscopy study of excitonic transitions in CuB2O4. We find that a large sublattice-sensitive antiferromagnetic linear dichroism (LD) emerges at the Néel temperature TN=21 K and show how it could simulate a “magnetic-field control of the crystal chirality.” We prove that the discovered LD is related microscopically to the magnetic Davydov splitting. This LD is highly sensitive to subtle changes in the spin subsystems, which allowed us to observe a splitting of the phase transition into an incommensurate magnetic phase into two transitions (T∗1=8.5 and T∗2=7.9 K) and to suggest elliptical spiral structures below T∗1, instead of a simple circular helix proposed earlier.О магнитном контроле кристаллической хиральности сообщил Сайто и др. [Phys. Rev. Lett. 101, 117402 (2008)] на основании экспериментов в CuB2O4. Это требование вызвало резкий спор в литературе, потому что это казалось, противоречат основным принципам симметрии. Мы урегулировать этот спор на основе исследования с помощью оптической спектроскопии высокого разрешения экситонных переходов в CuB2O4. Мы считаем, что большой подрешетко-чувствительный антиферромагнитный линейный дихроизм (LD) возникает при температуре Нееля TN= 21 Kи показываем, как это может имитировать "контроль магнитным полем кристаллической хиральности." Мы докажем, что обнаруженный LD связанс микроскопическим магнитным Давыдовским расщеплением. Этот Л.Д. весьма чувствителен к тонким изменениям в спиновых подсистем, которые позволили нам наблюдать расщепление фазового перехода в несоизмеримы магнитная фаза в двух переходов (T*1= 8,5 и Т*2 = 7,9 К) и предположить эллиптическую спиральную структуру ниже T*1, вместо простой круговой спирали предложенный ранее.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Martynov S. N.
Заглавие : Antisymmetric Exchange in the CuB2O4 A Subsystem
Место публикации : JETP Letters. - 2009. - Vol. 90, Is. 1. - P.55-58. - ISSN 0021-3640, DOI 10.1134/S0021364009130116
Примечания : Cited References: 31
Предметные рубрики: TRANSVERSE MAGNETIC-FIELD
FLUCTUATION-INDUCED PHASE
COPPER METABORATE
ANTIFERROMAGNETIC CHAINS
SOLITON LATTICE
INDUCED GAP
SPIN-WAVES
BA2CUGE2O7
CSCUCL3
MNSI
Аннотация: The space distribution of the components of the microscopic Hamiltonian of the antisymmetric Dzyaloshinskii-Moriya exchange with respect to the exchange bond pairs of the A subsystem of Cu2+ ions in the crystallographic 4b positions of CuB2O4 has been obtained using symmetry analysis. The possibility of the coexistence of two different types of the exchange spatial distribution is demonstrated. The component of the anti-symmetric exchange vector D parallel to the tetragonal axis has a weakly ferromagnetic distribution for all of the directions of the bonds between the nearest magnetic neighbors. Each exchange bond has an additional component of the antisymmetric exchange parallel to the bond projection on the tetragonal plane. The spatial distribution of these components is helicoidal with the modulation vector in the tetragonal crystal plane.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Yasuda Y., Nakamura H., Fujii Y., Kikuchi H., Chiba M., Yamamoto Y., Hori H., Petrakovskii G. A., Popov M. A., Bezmaternykh L. N.
Заглавие : B-11-NMR study of low-temperature phase transition in CuB2O4
Разночтения заглавия :авие SCOPUS: 11B-NMR study of low-temperature phase transition in CuB 2O4
Место публикации : J. Phys.: Condens. Matter: IOP PUBLISHING LTD, 2007. - Vol. 19: International Conference on Highly Frustrated Magnetism (AUG 15-19, 2006, Osaka, JAPAN), Is. 14. - Ст.145277. - ISSN 0953-8984, DOI 10.1088/0953-8984/19/14/145277
Примечания : Cited References: 10
Предметные рубрики: COPPER METABORATE
Ключевые слова (''Своб.индексиров.''): copper compounds--low temperature effects--magnetic field effects--nuclear magnetic resonance--b t phase diagram--dzialoshinskii moriya interaction--phase transitions
Аннотация: The material CuB2O4 presents a variety of phases in the B - T phase diagram, caused by the frustration and the Dzialoshinskii - Moriya interaction. In order to investigate the nature of the phase transitions, a B-11- NMR experiment on CuB2O4 has been performed under an applied magnetic field along the a- axis down to 0.4 K. A new incommensurate - incommensurate phase transition has been found at 0.8 K under a field of 0.5 T. Further, another phase transition has been observed at 4.7 K under a field of about 2 T, which is consistent with the transition reported by the neutron diffraction experiment.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Chudin O. S., Verpekin V. V., Burmakina G. V., Vasiliev A. D., Pavlenko N. I., Rubaylo A. I.
Заглавие : Chemistry of vinylidene complexes. XXII. Synthesis and physicochemical properties of the binuclear vinylidene complex [Cp(CO)(2)ReCu(mu-C=CHPh)(mu-Cl)](2). Molecular structure of the new rheniumcopper complex
Коллективы : Presidium of the Russian Academy of Sciences [8.15]
Место публикации : J. Organomet. Chem.: Elsevier Science, 2014. - Vol. 757. - P.57-61. - ISSN 0022-328X, DOI 10.1016/j.jorganchem.2013.12.050. - ISSN 1872-8561
Примечания : Cited References: 19. - This work was financially supported by the Presidium of the Russian Academy of Sciences (Program for Basic Research, Project No. 8.15).
Предметные рубрики: LIGANDS
Ключевые слова (''Своб.индексиров.''): rhenium--copper--vinylidene complexes--heterometallic complexes--x-ray structure--cyclic voltammetry
Аннотация: The interaction between Cp(CO)2ReCCHPh (1) and CuCl results in the new heterometallic μ-vinylidene complex [Cp(CO)2ReCu(μ2-CCHPh)(μ2-Cl)]2 (2) characterized earlier by IR and 1H, 13C NMR spectra. The molecular structure of compound 2 has been determined by X-ray diffraction analysis, revealing a dimer structure with two binuclear fragments linked to each other by asymmetric chloride bridges. The electrochemical behavior of 2 in acetonitrile was studied by cyclic voltammetry at a Pt-electrode.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Boehm M., Roessli B., Schefer J., Ouladdiaf B., Kulda J., Petrakovskii G. A.
Заглавие : Coexisting 1D and 3D magnetic interactions in the insulating copper-oxygen compound CuB2O4
Разночтения заглавия :авие SCOPUS: Coexisting 1D and 3D magnetic interactions in the insulating copper-oxygen compound CuB2 O4
Место публикации : Physica B: ELSEVIER SCIENCE BV, 2006. - Vol. 378-80: International Conference on Strongly Correlated Electron Systems (SECES 05) (JUL 26-30, 2005, Vienna, AUSTRIA). - P1128-1129. - ISSN 0921-4526, DOI 10.1016/j.physb.2006.01.540
Примечания : Cited References: 8
Предметные рубрики: SPIN-WAVE SPECTRUM
PHASE 10 K
METABORATE
Ключевые слова (''Своб.индексиров.''): cuprates--magnetic soliton lattice--heisenberg exchange--low-dimensional excitations--cuprates--heisenberg exchange--low-dimensional excitations--magnetic soliton lattice--dispersions--insulating materials--magnetic properties--neutron scattering--positive ions--cuprates--heisenberg exchange--low-dimensional excitations--magnetic soliton lattice--copper compounds
Аннотация: We performed inelastic neutron scattering measurements on CuB2O4 with a magnetic field applied in the tetragonal basal plane. The spin dynamics in this cuprate is determined by the interplay of two magnetic Cu2+ subsystems, the magnetic cage with predominant 3d Heisenberg exchange and quasi Id zig-zag chains. The comparison of the dispersion spectra along the chain direction in zero field and under applied field suggests a decoupling of the two magnetic sublattices under field. (c) 2006 Elsevier B.V. All rights reserved.
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13.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Внукова, Наталья Григорьевна, Лопатин, Владислав Александрович, Осипова, Ирина Владимировна, Чурилов, Григорий Николаевич
Заглавие : Comparative characteristics of alternating current light source with copper and silver electrodes under power samples analysis
Коллективы : "Современный атомно-эмиссионный анализ и науки о земле", семинар, Российская академия наук, Сибирское отделение РАН, Иркутский научынй центр СО РАН, Институт геохимии им. А. П. Виноградова СО РАН
Место публикации : Современный атомно-эмиссионный анализ и науки о земле: программа и тезисы докл. науч. семинара с междунар. участием, посвящ. 150-летию создания Кирхгофом и Бунзеном основ атом. спектроскопии, 30 июня - 4 июля 2009 г., г. Иркутск/ [отв. ред.: Е. В. Шабанова, О. В. Зарубина]. - 2009. - С. 17-18. - ISBN 978-5-94797-139-2
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14.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Ovchinnikov S. G.
Заглавие : Comparison of electronic structure, magnetic mechanism, and symmetry of pairing in ruthenates and cuprates
Место публикации : Ruthenate and rutheno-cuprate materials: unconventional superconductivity, magnetism and quantum phase transitions. Ser. lecture notes in physics: Springer Verlag, 2002. - Vol. 603: International Conference on Ruthenate and Rutheno-Cuprate Materials (OCT 25-27, 2001, VIETRI SUL MARE, ITALY). - P.239-255. - ISBN 0075-8450. - ISBN 3-540-44275-8
Примечания : Cited References: 48
Предметные рубрики: METAL-INSULATOR-TRANSITION
SUPERCONDUCTOR SR2RUO4
LAYERED PEROVSKITE
BAND-STRUCTURE
CORRELATED ELECTRONS
MOTT TRANSITION
COPPER OXIDES
HUBBARD-MODEL
RUSR2GDCU2O8
CA2-XSRXRUO4
Аннотация: A generalized tight-binding (GTB) method is developed to calculate quasi-particle band structure with explicit account for strong electronic correlations. The GTB method combines exact diagonalization of the multi-orbital P-d model Hamiltonian within the unit cell and the perturbation theory in the Hubbard X-operators form for the inter-cell hopping and interactions. For undoped cuprates we obtain the valence band structure in excellent agreement with ARPES data, evolution of the band structure with doping with an in-gap state at small doping, impurity-like band at higher doping to optimally doped metal. The effective low-energy Hamiltonian has the form of singlet-triplet t-J model. For ruthenates the t-J-I model is proposed with both antiferromagnetic J and ferromagnetic I couplings. In the strong correlation limit, the mean-field theory of superconductivity results in d-wave singlet pairing mediated by J (cuprates) and p-wave triplet one mediated by I (ruthenates) with ratio T-c((d))/T-c((p)) similar to 100 due to the different symmetry of the gap. The competition of ferromagnetic and antiferromagnetic order in rutheno-cuprates is also discussed.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kuz'min E. V., Ovchinnikov S. G., Baklanov I. O.
Заглавие : Comparison of superconductivity in Sr2RuO4 and copper oxides
Место публикации : Phys. Rev. B: AMER PHYSICAL SOC, 2000. - Vol. 61, Is. 22. - P15392-15397. - ISSN 1098-0121, DOI 10.1103/PhysRevB.61.15392
Примечания : Cited References: 21
Предметные рубрики: T-J MODEL
HUBBARD-MODEL
LAYERED PEROVSKITE
ELECTRONS
Аннотация: To compare the superconductivity in strongly correlated electron systems with the antiferrornagnetic fluctuations in the copper oxides and with the ferromagnetic fluctuations in Sr2RuO4 a t-J-l model is proposed. The antiferromagnetic coupling J results in the superconducting state of d(x2-y2) symmetry and the ferromagnetic coupling I results in the spin-triplet p-type state. The difference in the gap anisotropies provides the large difference in T-c values, for the typical values of the coupling constants: T-c similar to 1 K for the ruthenste and T-c similar to 100 K for the cuprates.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Boehm M., Roessli B., Schefer J., Wills A. S., Ouladdiaf B., Lelievre-Berna E., Staub U., Petrakovskii G. A.
Заглавие : Complex magnetic ground state of CuB2O4
Место публикации : Phys. Rev. B: AMER PHYSICAL SOC, 2003. - Vol. 68, Is. 2. - Ст.24405. - ISSN 1098-0121, DOI 10.1103/PhysRevB.68.024405
Примечания : Cited References: 16
Предметные рубрики: COPPER METABORATE
SCATTERING
Аннотация: The magnetic ground-state of copper metaborate CuB2O4 was investigated with unpolarized and polarized neutron scattering. A phase transition was found at T-N = 21 K to a commensurate weakly ferromagnetic state followed by a second transition at T* = 10 K to an incommensurate magnetic structure. Neutron diffraction revealed a continuously changing magnetic propagation vector below T*, and unusually asymmetric magnetic satellite reflections. Additionally, diffuse scattering is observed in the temperature range 1.5 K less than or equal to Tless than or equal to 30 K. The magnetic structure determined in both phases are shown to be consistent with results of symmetry analysis. In particular, we find that only one of the two inequivalent Cu2+ sublattice fully orders down to the lowest temperature. Our results show that the complex magnetic behavior of copper metaborate is a consequence of mutual interaction between the two Cu2+ sublattices with different ordering temperatures.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shneyder E. I., Ovchinnikov S. G., Shnurenko A. V.
Заглавие : Contribution of the non-Heisenberg ring exchange to the magnetic mechanism of high-Tc superconductivity
Место публикации : JETP Letters. - 2012. - Vol. 95, Is. 4. - P.193-197. - ISSN 0021-3640, DOI 10.1134/S0021364012040078
Примечания : Cited References: 44. - This work was supported by the Council of the President of the Russian Federation for Support of Young Scientists and Leading Scientific Schools (project no. NSh-1044.2012.2), by the Russian Foundation for Basic Research (project no. 12-02-00040), by the Presidium of the Russian Academy of Sciences (program no. 20 "Quantum Mesoscopic and Disordered Systems"), jointly by the Siberian and Ural Branches of the Russian Academy of Sciences, by Siberian Federal University (project no. s/b S-11), and by the Ministry of Education and Science of the Russian Federation (state contract no. P891, federal program "Human Capital"). E.I.Sh. acknowledges the support of the Dynasty Foundation.
Предметные рубрики: BAND HUBBARD-MODEL
COPPER OXIDES
ELEMENTARY EXCITATIONS
SPIN
ELECTRON
STATE
T/U
Аннотация: The effect of non-Heisenberg four-spin ring exchange on the superconducting transition temperature in strongly correlated electron systems is studied. It is shown that the ring exchange can significantly suppress the contribution of the Heisenberg exchange to superconducting pairing.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Popkov S. I., Semenov S. V., Bykov A. A., Sabitova E. I., Dubrovskiy A. A., Shaikhutdinov K. A., Petrov M. I.
Заглавие : Contributions from Inter-grain Boundaries to the Magneto-resistive Effect in Polycrystalline High-T (C) Superconductors. The Underlying Reason of Different Behavior for YBCO and BSCCO Systems
Разночтения заглавия :авие SCOPUS: Contributions from inter-grain boundaries to the magneto-resistive effect in polycrystalline high-TC superconductors. the underlying reason of different behavior for YBCO and BSCCO systems
Место публикации : J. Supercond. Nov. Magn: SPRINGER, 2011. - Vol. 24, Is. 7. - P2129-2136. - ISSN 1557-1939, DOI 10.1007/s10948-011-1166-9
Примечания : Cited References: 30. - This work is supported by program N5 of RAS, project N7.
Предметные рубрики: HIGH-TEMPERATURE SUPERCONDUCTORS
PHASE-SLIP
TRANSPORT-PROPERTIES
TRANSITION
FIELD
COMPOSITES
BULK
TAPES
YBA2CU3O7-DELTA
DISSIPATION
Ключевые слова (''Своб.индексиров.''): bscco--ybco--intergrain boundaries--magnetoresistance--bscco--intergrain boundaries--magnetoresistance--ybco--bscco--bscco system--comparative studies--high tc superconductors--high-field--inter-grain--irreversibility lines--magneto-resistive effect--polycrystalline--resistive transition--standard measurements--weak pinning--ybco--bismuth--electric resistance--grain boundaries--high temperature superconductors--lead--magnetic fields--magnetoelectronics--magnetoresistance--magnetos--superconductivity--yttrium barium copper oxides--semiconductor metal boundaries
Аннотация: In order to clarify the mechanisms in charge of broadening of resistive transition R(T) in magnetic fields of bismuth-based polycrystalline high-T (C) superconductor (HTSC), a comparative study of Bi1.8Pb0.3Sr1.9Ca2Cu3O (x) (BSCCO) and YBa2Cu3O7-delta (YBCO) have been performed. Magnetoresistive effects and irreversibility line obtained from magnetic measurements have been studied. It was established that (1) for YBCO, the smooth part of R(T) dependence unambiguously corresponds to dissipation in the intergrain boundaries for arbitrary magnetic fields; (2) for polycrystalline BSCCO, the smooth part of R(T) dependences correspond to dissipation within intergrain boundary subsystem in the field range H 10(2) Oe only, while standard measurements of R(T) dependences in magnetic field range H 10(2) Oe reflect the dissipation processes occurring both in intergrain boundary and HTSC grain subsystems; (3) for the high-field range, the contribution from intergrain boundaries of BSCCO can be distinguished from magnetoresistance R(H) dependences obtained at high enough current density on textured samples. It is proposed that various magneto-resistive properties of these classical HTSC systems are due comparatively weak pinning in BSCCO.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Saikova, Svetlana, Pavlikov, Aleksandr, Karpov, Denis, Samoilo, Aleksandr, Kirik, Sergey, Volochaev M. N., Trofimova, Tatyana, Velikanov D. A., Kuklin, Artem
Заглавие : Copper ferrite nanoparticles synthesized using anion-exchange Resin: Influence of synthesis parameters on the cubic phase stability
Место публикации : Materials. - 2023. - Vol. 16, Is. 6. - Ст.2318. - ISSN 19961944 (eISSN), DOI 10.3390/ma16062318
Примечания : Cited References: 67. - The Russian team acknowledges the support of the Russian Science Foundation (Project 22-73-10047)
Аннотация: Copper ferrite is of great interest to researchers as a material with unique magnetic, optical, catalytic, and structural properties. In particular, the magnetic properties of this material are structurally sensitive and can be tuned by changing the distribution of Cu and Fe cations in octahedral and tetrahedral positions by controlling the synthesis parameters. In this study, we propose a new, simple, and convenient method for the synthesis of copper ferrite nanoparticles using a strongly basic anion-exchange resin in the OH form. The effect and possible mechanism of polysaccharide addition on the elemental composition, yield, and particle size of CuFe2O4 are investigated and discussed. It is shown that anion-exchange resin precipitation leads to a mixture of unstable cubic (c-CuFe2O4) phases at standard temperature and stable tetragonal (t-CuFe2O4) phases. The effect of reaction conditions on the stability of c-CuFe2O4 is studied by temperature-dependent XRD measurements and discussed in terms of cation distribution, cooperative Jahn–Teller distortion, and Cu2+ and oxygen vacancies in the copper ferrite lattice. The observed differences in the values of the saturation magnetization and coercivity of the prepared samples are explained in terms of variations in the particle size and structural properties of copper ferrite.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrova A. E., Pankrats A. I.
Заглавие : Copper metaborate CuB2O4 phase diagrams bAsed on the results of measuring the magnetic moment
Место публикации : J. Exp. Theor. Phys. - 2018. - Vol. 126, Is. 4. - P.506-513. - ISSN 10637761 (ISSN), DOI 10.1134/S1063776118030172
Примечания : Cited References: 18. - This work was supported in part by the Russian Foundation for Basic Research (project no. 18-02-00183-a) and the program “Condensed Matter Physics and New-Generation Materials” of the Presidium of the Russian Academy of Sciences.
Ключевые слова (''Своб.индексиров.''): copper metaborate--magnetic phase transitions--multiferroics
Аннотация: The magnetic phase transitions and the phase diagrams of the CuB2O4 multiferroic are studied. Phase diagrams of copper metaborate in a magnetic field directed along the [100] and [001] axes are plotted using the results of measuring the magnetic moment. Evidences for the existence of polycritical points are obtained.
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