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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Маньков, Юрий Иннокентьевич
Заглавие : Электромагнитные волны с отрицательной групповой скоростью в случайно-неоднородном джозефсоновском переходе
Место публикации : Физ. тверд. тела. - 2013. - Т. 55, Вып. 5. - С. 850-854
Аннотация: Методом усредненных функций Грина исследованы электромагнитные волны в случайно-неоднородном джозефсоновском переходе при немонотонном спаде корреляций неоднородностей. Изучены модификация спектра и затухание этих возбуждений, обусловленные пространственными флуктуациями критического тока джозефсоновского перехода. Определены области значений частоты, волнового числа и стохастических параметров среды, при которых волны имеют отрицательную групповую скорость.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Val'kov V. V., Aksenov S. V.
Заглавие : Electron transport through Josephson junction containing a dimeric structure
Место публикации : J. Low Temp. Phys.: Springer, 2016. - Vol. 185, Is. 5-6. - P.446-452. - ISSN 00222291 (ISSN), DOI 10.1007/s10909-016-1545-5
Примечания : Cited References: 23. - This study was supported by the Presidium of the Russian Academy of Sciences, Program "Actual problems of low temperature physics”; the Russian Foundation for Basic Research, Projects Nos. 13-02-00523, 14-02-31280, and 15-42-04372; and the Scholarship of the President of the Russian Federation No. SP-6361.2013.5
Ключевые слова (''Своб.индексиров.''): josephson junction--andreev reflection--spin-flip processes--spin dimer
Аннотация: The dc Josephson effect in a superconductor/dimeric molecule/superconductor junction has been investigated by means of the nonequilibrium Green’s function method and the Keldysh diagram technique. The application of the atomic representation has allowed to simplify considerably the computation of the supercurrent and occupation numbers and receive the general expressions which take into account all processes of the Andreev reflection in the loopless approach. It is significant that the expressions for the current and occupation numbers are valid for different multilevel structures in the Josephson junction. The sf-exchange interaction between the electron spin and the spins of the dimer leads to the suppression of the critical current due to a new set of Andreev bound states. © 2016, Springer Science+Business Media New York.
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3.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Val'kov V. V., Aksenov S. V.
Заглавие : Effect of spin-flip processes on the Josephson current through a layer containing spin dimers
Коллективы : "Spin physics, spin chemistry, and spin technology", Internnational conference, Физико-технический институт им. А.Ф. Иоффе РАН, Казанский физико-технический институт им. Е. К. Завойского Казанского научного центра РАН, "Инно-мир", центр межрегионального инновационного развития
Место публикации : Int. conf. "Spin physics, spin chem., and spin technol.". - 2015. - P.44
Примечания : Библиогр.: 3 назв.
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4.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Val'kov V. V., Aksenov S. V.
Заглавие : Andreev bound states and the Josephson current through a spin dimeric structur
Коллективы : "Spin Waves", International Simposium, Физико-технический институт им. А.Ф. Иоффе РАН
Место публикации : Spin Waves 2015, Int. Symp.: abstracts. - СПб., 2015. - P.126
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shaihutdinov K. A., Balaev D. A., Gokhfeld D. M., Popkov S. I., Petrov M. I.
Заглавие : Transport properties of HTSC-based composites: Modeling the random networks of Josephson weak links with magneto-active barriers.
Коллективы : NATO Advanced Research Workshop on Vortex Dynamics in High-Temperature Superconductors
Разночтения заглавия :авие SCOPUS: Transport properties of HTSC- based composites: Modeling the random networks of Josephson weak links with magneto-active barriers
Место публикации : J. Low Temp. Phys./ NATO Advanced Research Workshop on Vortex Dynamics in High-Temperature Superconductors (2002 ; May ; 17-22). - 2003. - Vol. 130, Is. 3-4. - P.347-381. - ISSN 0022-2291, DOI 10.1023/A:1022204705059
Примечания : Cited References: 89
Предметные рубрики: CURRENT-VOLTAGE CHARACTERISTICS
HIGH-TEMPERATURE SUPERCONDUCTORS
SNS JUNCTIONS
THERMAL FLUCTUATIONS
RESISTIVE PROPERTIES
PERCOLATION SYSTEM
TRANSITION
YBA2CU3O7
BOUNDARY
OXIDES
Ключевые слова (''Своб.индексиров.''): crystalline materials--electric insulators--josephson junction devices--magnetic devices--magnetic barriers--superconducting materials--composite
Аннотация: The results of the study of transport properties (temperature dependences of resistivity and critical current, current-voltage characteristics) of two-phase composites on the basis of Y3/4Lu1/4Ba2Cu3O7 high-temperature superconductor (HTSC) produced by fast baking technique and modelling networks of Josephson-type weak links are reported. Non-superconducting ingredients with different magnetic structures, insulators and normal metals, function as barriers between HTSC crystallites. Besides strong suppression of superconducting properties in HTSC composites with magnetic barriers, anomalous behavior of temperature dependences of resistivity below T-c of HTSC grains have been observed and investigated.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shaikhutdinov K. A., Balaev D. A., Popkov S. I., Petrov M. I.
Заглавие : Transport and magnetic properties of Y3/4Lu1/4Ba2Cu3O7+Y3Fe5O12 composites representing a Josephson-type superconductor-ferrimagnet-superconductor weak-link network
Разночтения заглавия :авие SCOPUS: Transport and Magnetic Properties of Y3/4Lu1/4Ba 2Cu3O7 + Y3Fe5O 12 Composites Representing a Josephson-Type Superconductor-Ferrimagnet-Superconductor Weak-Link Network
Место публикации : Phys. Solid State: AMER INST PHYSICS, 2003. - Vol. 45, Is. 10. - P1866-1873. - ISSN 1063-7834, DOI 10.1134/1.1620087
Примечания : Cited References: 36
Предметные рубрики: RESISTIVE PROPERTIES
JUNCTION NETWORK
SYSTEM
TRANSITION
CURRENTS
VOLTAGE
STATE
FIELD
Аннотация: Y3/4Lu1/4Ba2Cu3O7 + Y3Fe5O12 composites with different volume ratios of the starting components were synthesized. The composites model an S-F-S Josephson junction network, where S stands for a superconductor and F, for a ferrimagnet. A study of the transport characteristics of the composites revealed that the temperature behavior of the electrical resistivity rho(T) below the superconducting transition point T-C is different in two regions separated by a temperature T-m. Below T-m, the current-voltage characteristics of the composites are nonlinear, while in the interval from T-C to T-m the values of rho(T) do not depend on the transport current j and magnetic field H. This behavior of rho(T, j ) and rho(T, H) is assigned to specific features of the tunneling of superconducting carriers through the ferrimagnetic layers separating HTSC grains in the composite. Magnetic measurements showed the diamagnetic response of HTSC grains to be lower in composites with a ferrimagnet. (C) 2003 MAIK "Nauka / Interperiodica".
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Dubrovskiy A. A., Shaykhutdinov K. A., Popkov S. I., Petrov M. I.
Заглавие : Time relaxation of residual resistance of HTSC-based composites
Место публикации : Physica C: ELSEVIER SCIENCE BV, 2007. - Vol. 460: 8th International Conference on Materials and Mechanisms of Superconductivity and High Temperature Superconductors (JUL 09-14, 2006, Dresden, GERMANY). - P1309-1310. - ISSN 0921-4534, DOI 10.1016/j.physc.2007.03.347
Примечания : Cited References: 5
Предметные рубрики: SUPERCONDUCTORS
Ключевые слова (''Своб.индексиров.''): granular htsc--resistance--relaxation--magnetic flux--granular htsc--magnetic flux--relaxation--resistance--copper oxides--crystallites--magnetic flux--magnetic relaxation--magnetization--yttrium barium copper oxides--anderson-like relaxation processes--flux trapping--residual resistance--time relaxation--josephson junction devices
Аннотация: Magnetoresistance curves R(H) and time relaxation of the residual resistance of bulk YBCO + CuO composites have been studied. These composites represent the network of Josephson junctions, where CuO acts as a barrier between YBCO grains. It has been shown that hysteresis of the R(H) dependences is related to the flux trapping within the YBCO crystallites. This flux induces magnetic field in the intergrain media. Time relaxation of the residual resistance is caused by relaxation of the magnetization of YBCO grains. The time dependence of the residual resistance obeys a logarithmic law, which describes the Anderson-like relaxation processes in the YBCO grains. (c) 2007 Elsevier B.V. All rights reserved.
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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shaykhutdinov K. A., Balaev D. A., Popkov S. I., Vasilyev A. D., Martyanov O. N., Petrov M. I.
Заглавие : Thermally activated dissipation in a novel foamed Bi-based oxide superconductor in magnetic fields
Место публикации : Supercond. Sci. Technol.: IOP PUBLISHING LTD, 2007. - Vol. 20, Is. 6. - P491-494. - ISSN 0953-2048, DOI 10.1088/0953-2048/20/6/001
Примечания : Cited References: 20
Предметные рубрики: FLUX
BI2SR2CACU2O8+DELTA
MECHANISM
PHASE
FILMS
Ключевые слова (''Своб.индексиров.''): bismuth compounds--josephson junction devices--magnetic field effects--transport properties--resistive transitions--thermally activated dissipation--oxide superconductors
Аннотация: The transport properties of a novel foamed superconductor Bi1.8Pb0.3Sr1.9Ca2Cu3Ox have been studied. As the analysis of resistive transitions in a magnetic field shows, the dissipation follows a thermally activated flux creep model with the temperature- independent pinning potential in S-N-S-type Josephson junctions.
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Popkov S. I., Shaihutdinov K. A., Petrov M. I.
Заглавие : The mechanisms responsible for broadening of the resistive transition under magnetic field in the Josephson junction network realized in bulk YBCO+CuO composites
Коллективы : International Workshop on Weak Superconductivity
Разночтения заглавия :авие SCOPUS: The mechanisms responsible for broadening of the resistive transition under magnetic field in the Josephson junction network realized in bulk YBCO + CuO composites
Место публикации : Physica C. - 2006. - Vol. 435, Is. 1-2. - P.12-15. - ISSN 0921-4534, DOI 10.1016/j.physc.2006.01.008
Примечания : Cited References: 15
Предметные рубрики: SUPERCONDUCTORS
MODEL
Ключевые слова (''Своб.индексиров.''): josephson network--ybco plus cuo composites--dissipation--magnetic field--dissipation--josephson network--magnetic field--ybco + cuo composites--composite materials--copper compounds--mathematical models--phase transitions--semiconductor junctions--yttrium compounds--creep model--josephson network--ybco + cuo composites--magnetic field effects
Аннотация: The experimental results of the effect of the magnetic field (up to 60 kOe) on the broadening of the resistive transition of bulk composites Y3/4Lu1/4Ba2CU3O7 (YBCO) + CuO are presented. These composites represent the network of the tunnel-type Josephson junctions where the copper oxide acts as a material forming barriers between YBCO crystallites. The mechanisms responsible for broadening of the resistive transition under magnetic field are discussed. The analysis of experimental R(7) dependences have shown that in the low field range 0-10(2) Oe, the R(7) dependences are described well by the Ambegaokar-Halperin (AH) model. In the range 10(3)-6 x 10(4) Oe, the dissipation follows Arrhenius law R similar to exp(-U(H)/k(B)T) characteristic for thermally activated flux creep model. In the range H similar to 10(2)-10(3), the crossover from AH to flux creep dissipation mechanisms occurs. (c) 2006 Elsevier B.V. All rights reserved.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Ospishchev S. V., Petrov M. I., Aleksandrov K. S.
Заглавие : The effect of paramagnetic impurities in normal metal on the critical current in a network of S-N-S Josephson junctions in bulk Y3/4Lu1/4Ba2Cu3O7+BaPb(1-x)Fe(x)O(3)composites
Разночтения заглавия :авие SCOPUS: The effect of paramagnetic impurities in normal metal on the critical current in a network of S-N-S Josephson junctions in bulk Y3/4Lu1/4Ba2Cu3O7 + BaPb1-xFexO3 composites
Место публикации : Supercond. Sci. Technol. - 2003. - Vol. 16, Is. 1. - P.60-64. - ISSN 0953-2048, DOI 10.1088/0953-2048/16/1/311
Примечания : Cited References: 41
Предметные рубрики: CURRENT-VOLTAGE CHARACTERISTICS
WEAK LINKS
RESISTIVE PROPERTIES
MAGNETIC-IMPURITIES
EXCHANGE FIELD
SNS JUNCTIONS
F-S
COMPOSITES
SUPERCONDUCTOR
SCATTERING
Ключевые слова (''Своб.индексиров.''): critical currents--interfaces (materials)--josephson junction devices--paramagnetism--transport properties--non-superconducting ingredient--paramagnetic impurities--superconductor normal metal superconductor--oxide superconductors
Аннотация: Bulk Y3/4Lu1/4Ba2Cu3O7 + BaPb1-xFexO3 composites representing a model of a network of superconductor-normal metal-superconductor (SNS) Josephson junctions with paramagnetic impurities (Fe) in the N layers have been prepared. The transport properties of the composites have been studied. An exponential decay of the critical current with increasing Fe content in the non-superconducting ingredient of the composite has been observed. Such a behaviour is accounted for in terms of the de Gennes proximity effect theory.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Isohatala J., Alekseev K. N., Kurki L. T., Pietilainen P.
Заглавие : Symmetry breaking in a driven and strongly damped pendulum
Место публикации : Phys. Rev. E: AMERICAN PHYSICAL SOC, 2005. - Vol. 71, Is. 6. - Ст.66206. - ISSN 1539-3755, DOI 10.1103/PhysRevE.71.066206
Примечания : Cited References: 37
Предметные рубрики: DC VOLTAGE GENERATION
SEMICONDUCTOR SUPERLATTICES
JOSEPHSON-JUNCTIONS
BLOCH OSCILLATIONS
FORCED PENDULUM
CHAOS
FREQUENCY
SYSTEMS
RECTIFICATION
STANDARD
Ключевые слова (''Своб.индексиров.''): periodically driven pendulums--symmetry breaking--bifurcation (mathematics)--damping--dynamics--nonlinear systems--semiconductor superlattices--pendulums
Аннотация: We examine the conditions for appearance of a symmetry breaking bifurcation in damped and periodically driven pendulums in the case of strong damping. We show that symmetry breaking, unlike other nonlinear phenomena, can exist at high dissipation. We prove that symmetry breaking phases exist between phases of symmetric normal and symmetric inverted oscillations. We find that symmetry broken solutions occupy a smaller region of the pendulum's parameter space in comparison to the statements made in earlier considerations [McDonald and Plischke, Phys. Rev. B 27, 201 (1983)]. Our research on symmetry breaking in a strongly damped pendulum is relevant to an understanding of the phenomena of dynamic symmetry breaking and rectification in pure ac driven semiconductor superlattices.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrov M. I., Balaev D. A., Shaikhutdinov K. A., Aleksandrov K. S.
Заглавие : Superconductor-semiconductor-superconductor junction network in bulk polycrystalline composites Y3/4Lu1/4Ba2Cu3O7 + Cu1-xLixO
Место публикации : Superconductor Science and Technology. - 2001. - Vol. 14, Is. 9. - P.798-805. - ISSN 0953-2048, DOI 10.1088/0953-2048/14/9/333
Ключевые слова (''Своб.индексиров.''): critical current density (superconductivity)--josephson junction devices--polycrystalline materials--superconductivity--thermal effects--transport properties--superconductor junction networks--semiconductor junctions
Аннотация: Bulk Y3/4Lu1/4Ba2Cu3O7 + Cu1-xLixO composites with x = 0, 0.003 and 0.06 and varied volume content of Cu1-xLixO have been prepared. Analysis of the transport properties of the composites has shown that they can be represented as a network of superconductor-semiconductor-superconductor (S-Sm-S) weak links. The dependence of the critical current density on the normal resistance for the composites studied shows a behaviour similar to that for single Josephson junctions. The experimental temperature dependences of the critical current are qualitatively described in terms of a theory of S-Sm-S junctions that takes into account the Andreev reflection of carriers from the S-Sm and Sm-S interfaces.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bykov A. A., Terent'ev K. Yu., Gokhfeld D. M., Savitskaya N. E., Popkov S. I., Petrov M. I.
Заглавие : Superconductivity on interfaces of nonsuperconducting granules La2CuO4 and La1.56Sr0.44CuO4
Место публикации : J. Supercond. Nov. Magn. - 2018. - Vol. 31, Is. 12. - P.3867–3874. - ISSN 15571939 (ISSN), DOI 10.1007/s10948-018-4668-x
Примечания : Cited References: 19. - The authors are grateful to D.A. Balaev for fruitful discussions, and I.V. Nemtsev for electronic microscope measurements in the center for shared use, KSC SB RAS. The work is supported by the Russian Science Foundation (project No. 17-72-10067).
Ключевые слова (''Своб.индексиров.''): magnetic properties--superconductivity--oxide superconductors--grain boundaries--lco--lsco--josephson media
Аннотация: Composite materials fabricated by annealing of nonsuperconducting ceramics La2CuO4 and La1.56Sr0.44CuO4 at 910 °C during various time are investigated. Areas of superconducting La1.85Sr0.15CuO4 phase arises at boundaries of contacting nonsuperconducting granules. The volume fraction of the superconducting phase increases with increasing annealing time. A model describing the magnetic and transport properties of the samples at low magnetic fields is constructed. The magnetotransport characteristics of obtained samples at low magnetic fields (∼ 100 Oe) are defined by weak links network formed by superconducting areas. At high fields, behavior of the system is defined by a magnetization of the disconnected superconducting islands. The average size of the superconducting areas has been estimated from an extended critical state model.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Dubrovskii A. A., Popkov S. I., Gokhfeld D. M., Semenov S. V., Shaikhutdinov K. A., Petrov M. I.
Заглавие : Specific features in the hysteretic behavior of the magnetoresistance of granular high-temperature superconductors
Место публикации : Phys. Solid State: MAIK Nauka-Interperiodica / Springer, 2012. - Vol. 54, Is. 11. - P.2155-2164. - ISSN 1063-7834, DOI 10.1134/S1063783412110030
Примечания : Cited References: 52. - This study was supported by the Russian Foundation for Basic Research within the framework of the Regional Competition SIBERIA (project no. 11-02-98007 r-sibir'_a).
Предметные рубрики: CURRENT-VOLTAGE CHARACTERISTICS
WEAK MAGNETIC-FIELDS
CRITICAL-CURRENT DENSITY
T-C SUPERCONDUCTORS
ANGULAR-DEPENDENCE
JOSEPHSON MEDIUM
TRANSPORT-PROPERTIES
CRITICAL-STATE
YBa2Cu3O7-DELTA
COMPOSITES
Аннотация: The behavior of the hysteresis of the magnetoresistance R(H) of granular high-temperature superconductors has been investigated under the conditions where the resistive response of the subsystem of grain boundaries close to saturation. The hysteretic dependences R(H) have been measured for Y1-xPrxBa2Cu3O7 samples at x = 0.11 and 0.04 with the transition temperatures T-C approximate to 85.5 and 91.0 K, respectively. The evolution of the field width of the hysteresis R(H) has been examined by varying the measuring current. The limit of the applicability has been established for the concept of the effective field in the intergranular medium, which was previously proposed for the description of the hysteretic behavior of the magnetoresistance R(H) and thermal magnetic prehistory of the granular high-temperature superconductors. In the studied samples, the approximation of the effective field in the intergranular medium is applicable until the magnetoresistance of the subsystem of grain boundaries exceeds (90 +/- 5)% of the maximum value.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrov M. I., Balaev D. A., Gokhfeld D. M.
Заглавие : Andreev reflection and experimental temperature dependences of the critical current in heterogeneous high-temperature superconductors (polycrystals and related composites)
Место публикации : Phys. Solid State: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2007. - Vol. 49, Is. 4. - P619-626. - ISSN 1063-7834, DOI 10.1134/S106378340704004X
Примечания : Cited References: 41
Предметные рубрики: CURRENT-VOLTAGE CHARACTERISTICS
NORMAL-METAL
WEAK LINKS
JOSEPHSON-JUNCTIONS
MODEL
SCATTERING
TRANSPORT
DISSIPATION
HYSTERESIS
Аннотация: The temperature dependences of the critical current of Y3/4Lu1/4Ba2Cu3O7 polycrystalline high-temperature superconductors subjected to annealing for different times and those of Y3/4Lu1/4Ba2Cu3O7 + BaPbO3 composites were measured. The results obtained were analyzed in terms of the Gunsenheimer-Schussler-Kummler theory considering the Andreev reflection of carriers in a "superconductor-normal metal-superconductor" (S-N-S) junction. Good agreement between the experimental and theoretical temperature dependences of the critical current over a wide temperature range for polycrystals with both natural and artificially created boundaries (composites) made it possible to estimate the effective length of grain boundaries in the high-temperature superconductors. It was revealed that the critical current density measured at 4.2 K is an exponential function of the length of grain boundaries in samples of both types.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Dubrovskiy A. A., Shaykhutdinov K. A., Popkov S. I., Petrov M. I.
Заглавие : Peculiarities of the time evolution of magnetoresistance of granular HTSC in a constant applied magnetic field
Коллективы :
Место публикации : Solid State Commun. - 2008. - Vol. 147, Is. 7-8. - P.284-287. - ISSN 0038-1098, DOI 10.1016/j.ssc.2008.05.044
Примечания : Cited References: 17. - This work was Supported by program "Quantum macrophysics" No. 3.4 of RAS and integration project No. 3.4 of SB RAS and in part by KSF, grant 18G011. D.A.B. and A.A.D. acknowledge the Russian Science Support Foundation.
Предметные рубрики: CRITICAL-STATE
SUPERCONDUCTORS
COMPOSITES
HYSTERESIS
RESISTANCE
Ключевые слова (''Своб.индексиров.''): superconductors--flux pinning and creep--tunneling--superconductors--flux pinning and creep--tunneling--agricultural products--carbon fiber reinforced plastics--copper oxides--electric conductivity--electric resistance--evolutionary algorithms--ferromagnetism--galvanomagnetic effects--grain (agricultural product)--health--hysteresis--magnetic devices--magnetic field effects--magnetic field measurement--magnetic fields--magnetic materials--magnetoelectronics--magnetoresistance--semiconductor metal boundaries--superconducting magnets--superconductivity--yttrium barium copper oxides--p ,p ,t measurements--applied (co)--applied magnetic fields--constant magnetic field (cmf)--elsevier (co)--evolution (co)--external fields--field induced--flux creep--hysteretic behavior--josephson couplings--low magnetic fields--magnetic (ce)--poly crystalline--superconducting grains--time evolutions--time relaxation--magnetism
Аннотация: The time evolution of the magnetoresistance of bulk YBCO + CuO composites at T = 4.2 K in constant applied magnetic fields was studied to clarify the mechanism of hysteretic behavior of magnetoresistance R(H) of granular HTSC. The composites represent "model" granular HTSC with weakened Josephson coupling between superconducting (YBCO) crystallites. It was found for the first time that on the ascending branch of R(H) dependence, the resistance at H = const decreased with time while on the descending branch, the resistance increased with time in ail applied constant magnetic field. In the range of low magnetic fields (below the minimum point of the descending branch of the R(H) dependence), the resistance at H const decreased again. Similar measurements performed oil pure polycrystalline YBCO at T = 77.4 K have shown that the behavior of evolution of resistance with time is similar to that observed for the composite. This proves the peculiarity of time evolution of maignetoresistance to be a common feature of granular HTSCs. The behavior revealed is well described by the model Of granular HTSC, where the intergrain media is in an effective magnetic field which is the superposition of the external field and the field induced by superconducting grains. The time evolution of resistance reflects the time relaxation of magnetization of HTSC grains due to the intragrain flux Creep Processes. (C) 2008 Elsevier Ltd. All rights reserved.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Dubrovskiy A. A., Popkov S. I., Shaikhutdinov K. A., Mart'yanov O. N., Petrov M. I.
Заглавие : Nonmonotonic Behavior of Magnetoresistance, R(H) Hysteresis, and Low-Temperature Heat Capacity of the BaPb0.75Bi0.25O3 Superconductor in a Magnetic Field: Possible Manifestations of Phase Separation
Коллективы :
Разночтения заглавия :авие SCOPUS: Nonmonotonic behavior of magnetoresistance, R(H) hysteresis, and low-temperature heat capacity of the BaPb0.75Bi0.25O 3 superconductor in a magnetic field: Possible manifestations of phase separation
Место публикации : J. Exp. Theor. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2010. - Vol. 110, Is. 4. - P584-593. - ISSN 1063-7761, DOI 10.1134/S1063776110040059
Примечания : Cited References: 27. - This study was performed under the program no. 5 of the Russian Academy of Sciences (project no. 7).
Предметные рубрики: ELECTRONIC SPECIFIC-HEAT
BAPB1-XBIXO3 SYSTEM
YBA2CU3O7-DELTA
COMPOSITES
TRANSITION
HTSCS
300-K
Ключевые слова (''Своб.индексиров.''): diamagnetic response--effective field--heat capacities--high-t--hysteretic dependence--josephson--low temperature heat capacities--non-monotonic dependence--nonmonotonic behaviors--polycrystalline--spatially inhomogeneous--transport currents--electric resistance--hysteresis--magnetic field effects--magnetic flux--magnetoelectronics--magnetoresistance--phase separation--semiconductor metal boundaries--specific heat--superconducting magnets--superconducting materials--superconductivity--transport properties--magnetic materials
Аннотация: The transport properties (R(T) and R(H) dependences at various values of the transport current in magnetic fields up to 65 kOe) and low-temperature heat capacity in magnetic fields up to 90 kOe of the BaPb0.75Bi0.25O3 superconductor (T-C approximate to 11.3 K) are investigated with the goal of clarifying the mechanisms determining the nonmonotonic behavior and hysteresis of its magnetoresistance R(H). The type of R(H) hysteretic dependences for BaPb0.75Bi0.25O3 is analogous to that observed in granular high-T-c superconductors (HTSCs); however, unlike classical HTSC systems, the field width of the magnetoresistance hysteresis loop for polycrystalline BaPb0.75Bi0.25O3 depends on the transport current. This means that although the mechanisms responsible for the magnetoresistance hysteresis (the influence of the magnetic flux trapped in super-conducting regions on the effective field in Josephson interlayers) are identical in these objects, the transport current in BaPb0.75Bi0.25O3 may considerably affect the diamagnetic response of the superconductor. A considerable effect of transport current on the field in which the R(H) dependences have a peak and exhibit hysterestic properties is observed. Such a behavior can be adequately interpreted using the model of the spatially inhomogeneous superconductor-insulator state proposed by Gorbatsevich et al. [JETP Lett. 52, 95 (1990)]. The nonmonotonic dependence of quantity C/T (C is the heat capacity) on the magnetic field discovered in the present study also agrees with the conclusions based on this model.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Popkov S. I., Shaikhutdinov K. A., Petrov M. I.
Заглавие : Mechanisms of dissipation in a Josephson medium based on a high-temperature superconductor in a magnetic field
Разночтения заглавия :авие SCOPUS: Mechanisms of dissipation in a josephson medium based on a high-temperature superconductor in a magnetic field
Место публикации : Phys. Solid State: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2006. - Vol. 48, Is. 5. - P826-832. - ISSN 1063-7834, DOI 10.1134/S1063783406050039
Примечания : Cited References: 32
Предметные рубрики: RESISTIVE TRANSITION
PHASE-SLIP
TRANSPORT-PROPERTIES
MAGNETORESISTANCE
SYSTEM
MODEL
YBA2CU3O7-X
PENETRATION
COMPOSITES
HYSTERESIS
Аннотация: This paper reports on the results of an investigation into the influence of magnetic fields (0-60 kOe) on the temperature dependences of the electrical resistance R(T) of the Y3/4Lu1/4Ba2Cu3O7 + CuO composites. The structure of these composites is considered to be a network of tunnel-type Josephson junctions in which a nonsuperconducting component (CuO) forms boundaries (barriers) between high-temperature superconducting crystallites. The temperature dependence R(T) of the composites has two steps characteristic of granular superconductors: (i) an abrupt change in the electrical resistance at the critical temperature of high-temperature superconducting crystallites and (ii) a smooth transition to the superconducting state under the influence of the boundaries between the crystallites. The experimental dependences R(T) are analyzed within the Ambegaokar-Halperin model of thermal fluctuations in Josephson junctions and the flux creep model. An increase in the magnetic field leads to a crossover from the Ambegaokar-Halperin mechanism to the flux creep mechanism. The temperature dependences R(T) in the range of weak magnetic fields (from 0 to 10(2) Oe) are adequately described by the relationship following from the Ambegaokar-Halperin model. In the range of strong magnetic fields (from 10(3) to 6 x 10(4) Oe), the dissipation obeys the Arrhenius law R similar to exp(-U(H)/T)], which is characteristic of the flux creep model with a temperature-independent pinning energy U(H). The effective Josephson coupling energies and the pinning energies corresponding to the Ambegaokar-Halperin and flux creep mechanisms are determined.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Dubrovskii A. A., Shaikhutdinov K. A., Popkov S. I., Gokhfeld D. M., Gokhfeld Yu. S., Petrov M. I.
Заглавие : Mechanism of the hysteretic behavior of the magnetoresistance of granular HTSCs: The universal nature of the width of the magnetoresistance hysteresis loop
Коллективы : Quantum Macrophysics of the Russian Academy of Sciences [3.4]; Krasnoyarsk Regional Science Foundation [18G011]; Foundation for Supporting National Science Projects
Место публикации : J. Exp. Theor. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2009. - Vol. 108, Is. 2. - P241-248. - ISSN 1063-7761, DOI 10.1134/S106377610902006X
Примечания : Cited References: 32. - This study was carried out under the program "Quantum Macrophysics" of the Russian Academy of Sciences and complex integration project no. 3.4 of the Siberian Branch of the Russian Academy of Sciences, and was partly supported by the Krasnoyarsk Regional Science Foundation (grant no. 18G011). D. A. B. and A. A. D. are grateful to the Foundation for Supporting National Science Projects.
Предметные рубрики: CRITICAL-CURRENT-DENSITY
HIGH-TEMPERATURE SUPERCONDUCTOR
CURRENT-VOLTAGE CHARACTERISTICS
EXTERNAL MAGNETIC-FIELD
BA-CU-O
JOSEPHSON MEDIUM
CRITICAL-STATE
FLUX
COMPOSITES
YBA2CU3O7-DELTA
Ключевые слова (''Своб.индексиров.''): barium--calcium--damping--electric resistance--high temperature superconductors--magnetic field effects--magnetic materials--magnetoelectronics--magnetoresistance--stiffness--classical systems--critical densities--experimental datum--external conditions--flux trapping--hysteretic behaviors--josephson vortices--residual resistances--transport currents--universal behaviors--y-ba-cu-o--hysteresis
Аннотация: The hysteretic behavior of the magnetoresistance R(H) of granular high-temperature superconductors (HTSCs) of the Y-Ba-Cu-O, Bi-Ca-Sr-Cu-O, and La-Sr-Cu-O classical systems is investigated for transport current densities lower and higher than the critical density (at H = 0). All systems exhibit universal behavior of the width of the magnetoresistance hysteresis loop: independence of transport current under identical external conditions. This means that flux trapping in HTSC grains is the main mechanism controlling the hysteretic behavior of the magnetoresistance of granular HTSCs, while pinning of Josephson vortices in the intragranular medium makes no appreciable contribution to the formation of magnetoresistance hysteresis (when transport current flows through the sample). Experimental data on relaxation of residual resistance after the action of a magnetic field also confirm this conclusion.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mankov Yu. I.
Заглавие : Electromagnetic waves in a randomly inhomogeneous Josephson junction
Место публикации : Tech. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2011. - Vol. 56, Is. 8. - P1147-1157. - ISSN 1063-7842, DOI 10.1134/S1063784211080172
Примечания : Cited References: 23
Предметные рубрики: DYNAMICS
Аннотация: Spectrum modification and damping of Josephson plasma waves induced by random inhomogeneities of the critical current through the superconductor contact and the averaged Green function of such excitations are analyzed. In the self-consistent approximation that makes it possible to take into account multiple wave scattering on the inhomogeneities, the frequency and damping of averaged waves, as well as position nu (m) and peak width Delta nu of the Fourier transform imaginary part of the averaged Green function, are determined as functions of wavevector k. The evolution of such functions with the variation of the correlation radius and the relative r.m.s. fluctuations of inhomogeneities is studied. The inhomogeneity-induced wave frequency decrease observed in the long wavelength spectral region qualitatively agrees with the nu (m) behavior. It is established that in the case of "long-range" inhomogeneities, the linear dependence of damping on k changes to the inversely proportional one, and damping tends to zero as k - 0, while Delta nu at small k attains its maximal values due to nonuniform broadening. In the presence of "short-range" inhomogeneities, the wave damping and Delta nu are found to be similar functions of k. The results are compared to the numerical calculation data.
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