Reentrant phenomena in superconductivity of ultrathin amorphous bismuth films

Белевцев, Б. И.; Komnik, Yu. F.; Фомин, А. В.

doi:10.1007/bf00683711

Cited by 19 publications

(23 citation statements)

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“…It is due to this fact that HTS crystals can exhibit negative magnetoresistance in magnetic fields applied parallel to layers. Such effect was observed in granular superconducting films exhibiting tunneling intergrain conductivity [4]. It was also found experimentally in NdBa.2Cu3Oc +x ceramics at the edge of the superconducting region [5] and in HTS monocrystals at temperatures higher than 71.…”

Section: Introductionsupporting

confidence: 63%

Negative Magnetoresistance of Layered High-t_cCompounds

1999

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Magnetoresistance of layered high-Tc systems with quasi-two-dimensional superconductivity in maguetic field II applied parallel to superconducting planes was investigated theoretically. In such configuration an increase iu the magnetic field inteusity decreases the critical temperature of superconducting regions. It canses both a. snppression of the gap parameter 4 and an increase iu the tunneling current. between the decoupled supercouducting plaues and, as a consequeuce, leads to negative magnetoresistance. The depeudence of tunneling current on H was calculated for superconducting layer thickness ds smaller than the superconducting correlation leugth. The results can be nsed for analysis of curreut-voltage characteristics of both supercondnctor-insulator-superconductor and superconductor-insnlatoruormal metal to multilayered tunnel structnres.

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Section: Introductionsupporting

confidence: 63%

Negative Magnetoresistance of Layered High-t_cCompounds

1999

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“…Теории [40,41] нашли качественное подтверждение для ультратон-ких аморфных пленок Bi [134,135]. Минимум сопротивления при T<T с0 появлялся для этих пленок при R Q Q , причем имелись случаи…”

Section: пр оводимость вышеunclassified

“…При этом кривые R(T), снятые при H=0 и Н ≠ 0, пересекаются, и при низких тем-пературах имеется отрицательное магнитосопротивление. Для более ре-зистивных образцов в [134,135] было обнаружено влияние на эффекты возврата приложенного напряжения V, а немонотонные зависимости с минимумом были зафиксированы не только для R(T), но и для R(H) и R(I) (I-ток). Известные модели квазивозвратного поведения в дисси-!…”

Section: пр оводимость вышеunclassified

“…Немонотонное поведе-ние R(I) было предсказано в [41]. Общим для обнаруженных в [134,135] немонотонных зависимостей сопротивления R от Т, Н или I является то, что повышение любой из этих переменных сопровождается усилением процессов распаривания. В качестве примера возможного влияния квантовых флуктуаций фазы на возвратные явления в пленках аморфного Bi [134,135] можно рассмотреть поведение R(I).…”

Section: пр оводимость вышеunclassified

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Superconductivity and localization of electrons in disordered two-dimensional metal systems

Белевцев¹

1990

Usp. Fiz. Nauk

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“…Other studies find within MFT that to have reentrance it is necessary to include off-diagonal capacitances [12], while others do not agree with this finding [9,[17][18][19]. The search for a reentrant type transition is encouraged by some evidence of low temperature instabilities found experimentally in arrays of Josephson junctions [2], ultrathin amorphous films [26], a multiphase high-T c system [27], and in granular superconductors [28].…”

Section: Introductionmentioning

confidence: 99%

Critical properties of two-dimensional Josephson-junction arrays with zero-point quantum fluctuations

Rojas

José

1996

Phys. Rev. B

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We present results from an extensive analytic and numerical study of a twodimensional model of a square array of ultrasmall Josephson junctions. We include the ultrasmall self and mutual capacitances of the junctions, for the same parameter ranges as those produced in the experiments. The model Hamiltonian studied includes the Josephson, E J , as well as the charging, E C , energies between superconducting islands. The corresponding quantum partition function is expressed in different calculationally convenient ways within its path-integral representation. The phase diagram is analytically studied using a WKB renormalization group (WKB-RG) plus a self-consistent harmonic approximation (SCHA) analysis, together with non-perturbative quantum Monte Carlo simulations. Most of the results presented here pertain to the superconductor to normal (S-N) region, although some results for the insulating to normal (I-N) region are also included. We find very good agreement between the WKB-RG and QMC results when compared to the experimental data. To fit the data, we only used the experimentally determined capacitances as fitting parameters. The WKB-RG analysis in the S-N region predicts a low temperature instability i.e. a Quantum Induced Transition (QUIT). We carefully analyze the possible existence of the QUIT via the QMC simulations and carry out a finite size analysis of T QU IT as a function of the magnitude of imaginary time axis L τ . We find that for some relatively large values of α = E C E J (1 ≤ α ≤ 2.25), the L τ → ∞ limit does appear to give a non-zero T QU IT , while for α ≥ 2.5, T QU IT = 0. We use the SCHA to analytically understand the L τ dependence of the QMC results with good agreement between them. Finally, we also carried out a WKB-RG analysis in the I-N region and found no evidence of a low temperature QUIT, up to lowest order in α −1 .

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Reentrant phenomena in superconductivity of ultrathin amorphous bismuth films

Cited by 19 publications

References 19 publications

Negative Magnetoresistance of Layered High-t_cCompounds

Negative Magnetoresistance of Layered High-t_cCompounds

Superconductivity and localization of electrons in disordered two-dimensional metal systems

Critical properties of two-dimensional Josephson-junction arrays with zero-point quantum fluctuations

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Reentrant phenomena in superconductivity of ultrathin amorphous bismuth films

Cited by 19 publications

References 19 publications

Negative Magnetoresistance of Layered High-tcCompounds

Negative Magnetoresistance of Layered High-tcCompounds

Superconductivity and localization of electrons in disordered two-dimensional metal systems

Critical properties of two-dimensional Josephson-junction arrays with zero-point quantum fluctuations

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Product

Resources

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Negative Magnetoresistance of Layered High-t_cCompounds

Negative Magnetoresistance of Layered High-t_cCompounds