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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Gohfeld D. M., Popkov S. I., Saihutdinov K. A., Petrov M. I.
Заглавие : High-temperature superconductor based composites: Large magnetoresistance in weak magnetic fields
Место публикации : Tech. Phys. Lett.: AMER INST PHYSICS, 2001. - Vol. 27, Is. 11. - P952-955. - ISSN 1063-7850, DOI 10.1134/1.1424404
Примечания : Cited References: 16
Предметные рубрики: CRITICAL CURRENTS
APPLICABILITY
TRANSITION
TRANSPORT
SYSTEM
CUO
Аннотация: It was found that high-temperature superconductor (HTSC) based composites of the 1-2-3 (YBCO) + dielectric and YBCO + normal metal types exhibit large magnetoresistances in weak magnetic fields in a broad temperature range. This behavior is qualitatively explained using the concept of the irreversibility line in HTSCs and the mechanism of thermal fluctuations in the network of weak bonds of the Josephson type realized in HTSC composites. The HTSC-based composites exhibit a much higher sensitivity (as compared to that in the usual HTSC ceramics) to weak magnetic fields (below 300 Oe) at liquid-nitrogen temperatures, which is important for practical applications. (C) 2001 MAIK "Nauka /Interperiodica".
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrov M. I., Balaev D. A., Shaikhutdinov K. A., Popkov S. I.
Заглавие : Anomalous transport properties of a paramagnetic NiTiO3+HTSC two-phase system representing a random Josephson junction network
Разночтения заглавия :авие SCOPUS: Anomalous transport properties of a paramagnetic NiTio3 + HTSC two-phase system representing a random Josephson junction network
Место публикации : JETP Letters. - 2002. - Vol. 75, Is. 3. - P.138-141. - ISSN 0021-3640, DOI 10.1134/1.1469500
Примечания : Cited References: 23
Предметные рубрики: RESISTIVE PROPERTIES
CRITICAL CURRENTS
SNS JUNCTIONS
COMPOSITES
Аннотация: Composites representing a network of random Josephson junctions and characterized by the compositions 92.5 at. % Y3/4Lu1/4Ba2Cu3O7 + 7.5 at. % NiTiO3 and 92.5 at. % Y3/4Lu1/4Ba2Cu3O7 + 7.5 at.% MgTiO3 are synthesized, and their magnetoresistance properties are studied. The temperature dependence of the resistance R(T) measured for the composite that contains the paramagnetic NiTiO3 compound exhibits a characteristic feature below the superconducting transition temperature T-c of the high-T-c superconductor, namely, a region where R is independent of the current j and weakly depends on the magnetic field H. Below a certain temperature T-m, a strong dependence of R on j and H is observed, which is peculiar to a network of Josephson junctions. The dependences R(T, j, H) obtained for the "reference" samples with the nonmagnetic MgTiO3 compound exhibit no such features. The anomalous behavior of the HTSC + NiTiO3 composite is explained by the effect produced by the magnetic moments of Ni atoms in the insulating barriers on the transport current. (C) 2002 MAIK "Nauka / Interperiodica".
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3.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Попков, Сергей Иванович
Заглавие : Экспериментальное изучение транспортных свойств композитов ВТСП+ферримагнетик
Коллективы : Всероссийская научная конференция студентов-физиков и молодых ученых, Ассоциация студентов-физиков и молодых учёных России, Российское физическое общество, Институт электрофизики УрО РАН, Красноярский государственный университет, Красноярский научный центр Сибирского отделения РАН
Место публикации : Девятая Всероссийская научная конференция студентов-физиков и молодых ученых (ВНКСФ-9): тезисы/ предс. науч. ком. М. В. Садовский. - 2003. - Секция: Физика низких температур, сверхпроводимость. - С. 277-278
Примечания : Библиогр.: 4
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Shaihutdinov K. A., Popkov S. I., Petrov M. I.
Заглавие : Controlled magnetoresistance in Y3/4Lu1/4Ba2Cu3O7-CuO composites at 77 K
Разночтения заглавия :авие SCOPUS: Controlled magnetoresistance in Y3/4Lu1/4Ba 2Cu3O7-CuO composites at 77 K
Место публикации : Tech. Phys. Lett.: AMER INST PHYSICS, 2003. - Vol. 29, Is. 7. - P578-581. - ISSN 1063-7850, DOI 10.1134/1.1598555
Примечания : Cited References: 17
Предметные рубрики: SUPERCONDUCTOR
Аннотация: We have studied the low-temperature magnetoresistance of Y3/4Lu1/4Ba2Cu3O7-CuO composites obtained by fast sintering technique and established a relation between the probing to critical current density ratio j/j(c) and the shape of the magnetoresistance curve rho(H). For j/j(c) 1, the electric resistance arises at a threshold value of the magnetic field strength H-c. For j/j(c) greater than or equal to 1, a linear variation of rho(H) at 77 K in the range from 0 to 14 Oe can be provided by selecting the CuO content (in the 15-30 vol % interval) and the j value (in the 0.003-0.2 A/cm(2) range). In the latter case, the slope drho/dH (i.e., the sensitivity of the electric resistivity with respect to the magnetic field) is 1-20 mOmega cm/Oe and the relative field-induced increase in the resistivity rho(0)
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrov M. I., Tetyueva T. N., Kveglis L. I., Efremov A. A., Zeer G. M., Shaihutdinov K. A., Balaev D. A., Popkov S. I., Ovchinnikov S. G.
Заглавие : Synthesis, microstructure, and the transport and magnetic properties of bi-containing high-temperature superconductors with a porous structure
Место публикации : Tech. Phys. Lett.: AMER INST PHYSICS, 2003. - Vol. 29, Is. 12. - P986-988. - ISSN 1063-7850, DOI 10.1134/1.1639450
Примечания : Cited References: 5
Аннотация: Preliminary data on the synthesis and physical properties of polycrystalline Bi1.8Pb0.3Sr2Ca2Cu3Ox high-temperature superconductors of low density with a foam-like microstructure are reported. (C) 2003 MAIK "Nauka / Interperiodica".
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Петров, Михаил Иванович, Тетюева Т. Н., Квеглис, Людмила Иосифовна, Ефремов А. А., Зеер Г. М., Шайхутдинов, Кирилл Александрович, Балаев, Дмитрий Александрович, Попков, Сергей Иванович, Овчинников, Сергей Геннадьевич
Заглавие : Синтез, микроструктура, транспортные и магнитные свойства висмутовых ВТСП с пористой структурой
Место публикации : Письма в журн. техн. физ. - 2003. - Т. 29, Вып. 23. - С. 40-45. - ISSN 0320-0116
ГРНТИ : 29.19.29
Аннотация: Приведены предварительные результаты по синтезу и исследованию физич. свойств поликристаллических ВТСП низкой плотности состава Bi[1.8]Pb[0.3]Sr[2]Ca[2]Cu[3]O[x], имеющих микроструктуру пены.
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7.

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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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Shaihutdinov K. A., Popkov S. I., Petrov M. I.
Заглавие : The effect of ferrimagnetic ordering in insulating component of composites HTSC plus Yttrium Iron Garnet on its transport properties
Разночтения заглавия :авие SCOPUS: The effect of ferrimagnetic ordering in insulating component of composites HTSC + yttrium iron garnet on its transport properties
Место публикации : Solid State Commun.: PERGAMON-ELSEVIER SCIENCE LTD, 2003. - Vol. 125, Is. 5. - P281-285. - ISSN 0038-1098, DOI 10.1016/S0038-1098(02)00602-6
Примечания : Cited References: 34
Предметные рубрики: SUPERCONDUCTOR
TRANSITION
CURRENTS
Ключевые слова (''Своб.индексиров.''): high-tc superconductors--heterojunctions--magnetically ordered materials--grain boundaries--heterojunctions--high-tc superconductors--magnetically ordered materials--grain boundaries--grain boundaries--heterojunctions--high temperature superconductors--transport properties--yttrium compounds--ferrimagnetic ordering--garnets
Аннотация: Composites Y3/4Lu1/4Ba2Cu3O7 + Y3Fe5O12 modeling random network superconductor-ferrimagnetic-superconductor have been prepared and their transport properties (temperature dependences of resistivity rho and critical current density j(c), current-voltage characteristics) have been studied. Below the superconducting transition temperature T-m the rho(T) dependences exhibit a kink at some temperature T-m. The crossover of current-voltage characteristics from ohmic-like behavior in range T-m/T-c to non-linear one below T-m is observed. Transport properties of the 'benchmark' composites Y3/4Lu1/4Ba2Cu3O7 + Y3Al5O12 are typical for network superconductor-insulator-superconductor Josephson junction. The behavior observed for Y3/4Lu1/4Ba2Cu3O7 + Y3Fe5O12 composites is attributed to peculiarities of supercurrent carriers tunnelling through ferrimagnetic barriers. (C) 2002 Elsevier Science Ltd. All rights reserved.
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9.

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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10.

Вид документа : Однотомное издание
Шифр издания :
Заглавие : Второй Сибирский семинар по высокотемпературной сверхпроводимости : программа
Выходные данные : Красноярск, 2004
Коллективы : Институт физики им. Л.В. Киренского Сибирского отделения РАН, Сибирский семинар по высокотемпературной сверхпроводимости (2; 2004 ; 1-2 дек.; Красноярск) :
Содержание : Сверхпроводимость пористых ВТСП/ М. И. Петров. Влияние магнитных корреляций и трехцентровых взаимодействий на фазовую диаграмму высокотемпературных сверхпроводников с dx2-e2 симметрией параметра порядка/ Д. М. Дзебисашвили. Релаксация электросопротивления в композитных ВТСП/ С. И. Попков. Механизмы диссипации в джозефсоновской среде на основе ВТСП под воздействием магнитного поля/ Д. А. Балаев. Вольт-амперные характенристики пористого Bi1.8Pb0.3Sr2Ca2Cu3Ox/ Д. М. Гохфельд. концентрационная зависимость зонной структуры купратов/ В. А. Гавричков. Влияние ближнего магнитного порядка на сверхпроводимость в эффективной синглет-триплетной модели оксидов меди/ М. М. Коршунов. Электрон-фононное взаимодействие в ВТСП купратах: эффективный гамильтониан/ Е. И. Шнейдер.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Shaihutdinov K. A., Popkov S. I., Gokhfeld D. M., Petrov M. I.
Заглавие : Large magneto-resistance of high-T-C superconductor based composites to low magnetic fields at the liquid nitrogen temperature
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). - P943-944. - ISSN 0921-4534, DOI 10.1016/j.physc.2004.03.173
Примечания : Cited References: 6
Ключевые слова (''Своб.индексиров.''): htsc--magnetic field sensors--magneto-resistance
Аннотация: The magneto-resistive effect in bulk 123YBCO + CuO and YBCO + Normal metal BaPbO3 composites prepared by fast backing technique has been studied. The composites exhibit broadening of resistive transition in low magnetic fields (less than 200 Oe) for a wide temperature range. Experimental dependences of resistivity versus magnetic field at various transport current densities are presented and discussed. The HTSC based composites exhibit a much higher sensitivity to weak magnetic fields at liquid nitrogen temperature, as compared to that for the "pure" HTSC ceramics. This effect is attractive for possible practical applications and may be used in magnetic field sensor devices. (C) 2004 Elsevier B.V. All rights reserved.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Shaihutdinov K. A., Popkov S. I., Gokhfeld D. M., Petrov M. I.
Заглавие : Magnetoresistive effect in bulk composites 1-2-3 YBCO+CuO and 1-2-3 YBCO+BaPb(1-x)SnxO(3) and their application as magnetic field sensors at 77 K
Разночтения заглавия :авие SCOPUS: Magnetoresistive effect in bulk composites 1-2-3 YBCO + CuO and 1-2-3 YBCO + BaPb1-xSnxO3 and their application as magnetic field sensors at 77 K
Место публикации : Supercond. Sci. Technol.: IOP PUBLISHING LTD, 2004. - Vol. 17, Is. 1. - P175-181. - ISSN 0953-2048, DOI 10.1088/0953-2048/17/1/031
Примечания : Cited References: 27
Предметные рубрики: PHASE-SLIP
SUPERCONDUCTOR
TEMPERATURE
YBA2CU3O7-DELTA
TRANSITION
Ключевые слова (''Своб.индексиров.''): ceramic materials--composite materials--critical current density (superconductivity)--high temperature operations--high temperature superconductors--lead compounds--magnetoresistance--sensors--yttrium barium copper oxides--high temperature superconductor ceramics--magnetic field sensors--magnetoresistive effect--transport current density--oxide superconductors
Аннотация: We have studied the magnetoresistive effect in bulk 1-2-3 YBCO + CuO and 1-2-3 YBCO + BaPb1-xSnxO3 composites prepared using the fast backing technique. We have found that the composites exhibit large magnetoresistance in low magnetic fields ( 100 Oe) for a broad temperature range. We have studied the experimental dependences of resistivity versus magnetic field at various transport current densities. The high-T-C superconductor (HTSC) based composites exhibit a much higher sensitivity to weak magnetic fields at liquid nitrogen temperature, compared to that for pure HTSC ceramics. This effect is attractive for practical applications and the composite materials can be used as active elements in magnetic field sensor devices.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Petrov M. I., Tetyueva T. N., Kveglis L. I., Efremov A. A., Balaev D. A., Shaikhutdinov K. A., Popkov S. I., Ovchinnikov S. G., Zeer E. P.
Заглавие : The synthesis, microstructure, transport and magnetic properties of Bi-based low density HTSC
Коллективы : Japanese/Mediterranean Workshop on Applied Electronmagnetic Engineering for Magnetic and Superconducting Materials/3rd Superconducting Flywheel Workshop
Место публикации : J. Mater. Process. Technol. - LAUSANNE: ELSEVIER SCIENCE SA, 2005. - Vol. 161, Is. 1-2. - С. 58-61. - APR 10. - ISSN 0924-0136, DOI 10.1016/j.jmatprotec.2004.07.056
Примечания : Cited Reference Count: 4
Аннотация: HTSC Bi1.8Pb0.3Sr2Ca2Cu3Ox of low density has been synthesized and its structural and physical properties have been studied. Scanning electron microscopy (SEM) image shows that the material obtained has porous "foam" structure. The levitation force measured for the porous Bi1.8Pb0.3Sr2Ca2Cu3Ox is appeared to be approximately the same as for polycrystalline YBCO of high density. These "foam" structures may be an ideal material for some practical applications of HTSCs in bulk form. (c) 2004 Elsevier B.V. All rights reserved.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gokhfeld D. M., Balaev D. A., Popkov S. I., Shaykhutdinov K. A., Petrov M. I.
Заглавие : Magnetization loop and critical current of porous Bi-based HTS
Место публикации : Physica C: ELSEVIER SCIENCE BV, 2006. - Vol. 434, Is. 2. - P135-137. - ISSN 0921-4534, DOI 10.1016/j.physc.2005.12.088
Примечания : Cited References: 11
Предметные рубрики: SUPERCONDUCTORS
Ключевые слова (''Своб.индексиров.''): porous superconductor--critical current--bean model--foam--bean model--critical current--foam--porous superconductor--hysteresis--magnetization--mathematical models--porous materials--bean model--critical current--foam--porous superconductor--superconductivity
Аннотация: The magnetization of porous Bi(1.8)Pb(0.3)Sr(2)Ca(2)Cu(3)O(x) has been investigated. The experimental magnetization hysteretic loops of M(H) were described in the frames of Val'kov-Khrustalev model developed for type II granular superconductors. (c) 2005 Elsevier B.V. All rights reserved.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Belozerova I. L., Gokhfeld D. M., Kashkina L. V., Kuzmin Y. I., Michel C. R., Petrov M. I., Popkov S. I., Shaikhutdinov K. A.
Заглавие : Current-voltage characteristics of a foamed Bi1.8Pb0.3Sr2Ca2Cu3Ox high-temperature superconductor with fractal cluster structure
Разночтения заглавия :авие SCOPUS: Current-voltage characteristics of a foamed Bi1.8Pb 0.3Sr2Ca2Cu3Ox high-temperature superconductor with fractal cluster structure
Место публикации : Phys. Solid State: SPRINGER, 2006. - Vol. 48, Is. 2. - P207-212. - ISSN 1063-7834, DOI 10.1134/S1063783406020016
Примечания : Cited References: 27
Предметные рубрики: T-C SUPERCONDUCTORS
NORMAL-PHASE
VORTEX MOTION
TRANSITION
TRANSPORT
VORTICES
Аннотация: The influence of the structure of foamed polycrystalline bismuth-based superconductors on their critical currents and current-voltage characteristics is studied. It is found that superconducting foams have a fractal structure, and the fractal dimension of the boundary between the normal and superconducting phases is estimated. The magnetic and transport properties of superconducting foams are investigated, and the current-voltage characteristics are obtained in a wide range of currents. The effect of percolation phenomena on vortex pinning in a foamed superconductor is considered. The current-voltage characteristics of the superconducting foams at the beginning of the resistive transition are found to be in good agreement with a model in which a magnetic flux is assumed to be trapped in the fractal clusters of a normal phase.
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16.

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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17.

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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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Popkov S. I., Shaikhutdinov K. A., Petrov M. I.
Заглавие : Investigation of the Josephson coupling through a magnetoactive barrier (ferrimagnet, paramagnet) in Y3/4Lu1/4Ba2Cu3O7+Y-3(Al1-xFex)(5)O-12 composites
Разночтения заглавия :авие SCOPUS: Investigation of the Josephson coupling through a magnetoactive barrier (ferrimagnet, paramagnet) in Y3/4Lu1/4Ba 2Cu3O7 + Y3(Al1 - X Fe x )5O12 composites
Место публикации : Phys. Solid State: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2006. - Vol. 48, Is. 11. - P2046-2055. - ISSN 1063-7834, DOI 10.1134/S1063783406110023
Примечания : Cited References: 41
Предметные рубрики: S-F-S
MAGNETIC-PROPERTIES
RESISTIVE PROPERTIES
JUNCTION NETWORK
SUPERCONDUCTOR
Y3FE5-XALXO12
TRANSITION
TRANSPORT
METAL
FIELD
Аннотация: The transport properties of two-phase composites consisting of a high-temperature superconductor and a nonsuperconducting component with magnetic ordering are analyzed. These composites are considered as a network of "superconductor-magnetoactive insulator-superconductor" weak links of the Josephson type. Substituted garnets Y-3(Al1 - x Fe (x) )(5)O-12 (x = 0, ..., 1.0) are used as a magnetoactive component. The composites under investigation contain 92.5 vol % Y3/4Lu1/4Ba2Cu3O7 (the high-temperature superconductor) and 7.5 vol % Y-3(Al1 - x Fe (x) )(5)O-12 (x = 0, ..., 1.0). It is shown that an increase in the iron content in the Y-3(Al1 - x Fe (x) )(5)O-12 garnet leads to a reduction of the Josephson coupling strength: the temperature range in which the electrical resistance of the composites is equal to zero is reduced, and the critical current density at a temperature of 4.2 K decreases exponentially. For composites in which the iron content in the Y-3(Al1 - x Fe (x) )(5)O-12 garnet is higher than 0.1, the temperature dependence of the electrical resistance R(T) at temperatures below the transition point T-C of high-temperature superconductor crystallites has a portion in the range T-m -T-C where the resistance R(T) is independent of the transport current and the magnetic field strength. Below the temperature T-m , the dependences of the electrical resistance R(T) of the composites are nonlinear functions of the current and involve a considerable contribution from magnetoresistance. This behavior is characteristic of a network of Josephson junctions. The temperature T-m decreases with an increase in the iron content in the Y-3(Al1 - x Fe (x) )(5)O-12 garnet. The appearance of the above feature in the temperature dependences of the electrical resistance R(T) is interpreted as complete suppression of the Josephson coupling in the temperature range above T (m) due to the interaction of supercurrent carrier pairs with magnetic moments of iron atoms in the dielectric barriers separating high-temperature superconductor grains.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shaykhutdinov K. A., Balaev D. A., Gokhfeld D. M., Kuzmin Y. I., Popkov S. I., Petrov M. I.
Заглавие : Study of current-voltage characteristics of Bi-based high-temperature superconductors with fractal cluster structure
Коллективы : International Workshop on Weak Superconductivity
Место публикации : Physica C. - 2006. - Vol. 435, Is. 1-2. - P.19-22. - ISSN 0921-4534, DOI 10.1016/j.physc.2006.01.010
Примечания : Cited References: 18
Предметные рубрики: NORMAL-PHASE
VORTEX MOTION
TRANSPORT
Ключевые слова (''Своб.индексиров.''): superconducting foam--pinning--critical current density--fractal--percolation--cluster--cluster--critical current density--fractal--percolation--pinning--superconducting foam--bismuth--critical current density (superconductivity)--electric currents--electric potential--foams--percolation (solid state)--polycrystalline materials--cluster--fractal--pinning--superconducting foam--superconducting materials
Аннотация: We study the effect of the structure on critical currents and current-voltage characteristics (CVC's) of foamed bismuth-based polycrystalline high-temperature superconductors (HTSC). The fractal cluster structure of superconducting foams has been observed and the fractal dimension of boundaries between superconducting and normal clusters has been determined. Based on the magnetic and transport properties of the foamed polycrystalline superconductors, we have shown that the initial parts of CVC's of the superconducting foams are described well by the model that accounts the magnetic flux trapping in fractal clusters of a normal phase. (c) 2006 Elsevier B.V. All rights reserved.
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20.

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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