Nonlinear Effects on the Conductivity of a Superconductor above Its Transition Temperature

Hurault, J.P.

doi:10.1103/physrev.179.494

Cited by 57 publications

(29 citation statements)

References 10 publications

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“…In the limit g → 0 the electric-field-dependent conductivity can be written in a simple form 15) and thus the nonlinear electric-field correction to the conductivity reads…”

Section: Paraconductivity In a Layered Metalmentioning

confidence: 99%

Fluctuation conductivity in superconductors in strong electric fields

Mishonov

Posazhennikova²,

Indekeu³

2002

Phys. Rev. B

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We study the effect of a strong electric field on the fluctuation conductivity within the timedependent Ginzburg-Landau theory for the case of arbitrary dimension. Our results are based on the analytical derivation of the velocity distribution law for the fluctuation Cooper pairs, from the Boltzmann equation. Special attention is drawn to the case of small nonlinearity of conductivity, which can be investigated experimentally. We obtain a general relation between the nonlinear conductivity and the temperature derivative of the linear Aslamazov-Larkin conductivity, applicable to any superconductor. For the important case of layered superconductors we derive an analogous relation between the small nonlinear correction for the conductivity and the fluctuational magnetoconductivity. On the basis of these relations we provide new experimental methods for determining both the lifetime constant of metastable Cooper pairs above Tc and the coherence length. A systematic investigation of the 3rd harmonic of the electric field generated by a harmonic current can serve as an alternative method for the examination of the metastable Cooper-pair relaxation time.

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“…In the limit g → 0 the electric-field-dependent conductivity can be written in a simple form 15) and thus the nonlinear electric-field correction to the conductivity reads…”

Section: Paraconductivity In a Layered Metalmentioning

confidence: 99%

Fluctuation conductivity in superconductors in strong electric fields

Mishonov

Posazhennikova²,

Indekeu³

2002

Phys. Rev. B

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“…As it can be noticed, we define the relaxation rate Γ −1 0 as depending on the actual temperature T , while in many other works, 3,19,23 it is defined as a function of the mean-field critical temperature, T 0 . Of course the difference is negligible near the transition point, but one must recall that in the derivation of the GL equations from the BCS theory, 21,24,25 the temperature is usually approximated with the critical one, while the reduced temperature ln (T /T 0 ) is approximated with (T − T 0 ) /T 0 .…”

Section: Tdgl Equation For Arbitrary Electric Fieldmentioning

confidence: 99%

“…2 However, it was shown that the fluctuation conductivity may be calculated in the linearresponse approximation only for sufficiently weak fields, when they do not perturb the fluctuation spectrum. 3 Reasonably high values of the electric field E can accelerate the fluctuating paired carriers to the depairing current, and thus, suppress the lifetime of the fluctuations, leading to deviation from Ohm's law. In connection with the low-temperature superconductors, the nonlinearity has been studied theoretically for the isotropic case 4,5 and also proven experimentally on thin aluminum films.…”

Section: Introductionmentioning

confidence: 99%

Critical fluctuation conductivity in layered superconductors in a strong electric field

Puica¹,

Lang

2003

Phys. Rev. B

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The paraconductivity, originating from critical superconducting order-parameter fluctuations in the vicinity of the critical temperature in a layered superconductor is calculated in the frame of the self-consistent Hartree approximation, for an arbitrarily strong electric field and zero magnetic field. The paraconductivity diverges less steep towards the critical temperature in the Hartree approximation than in the Gaussian one and it shows a distinctly enhanced variation with the electric field. Our results indicate that high electric fields can be effectively used to suppress orderparameter fluctuations in high-temperature superconductors.

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“…The mechanism can be summarized by saying that reasonably high values of the electric field, comparable to the so-called critical field E c (T ), can accelerate the fluctuating paired carriers to the depairing current, and thus, suppress the lifetime of the fluctuations, leading to deviation from Ohm's law. The non-Ohmic behavior of the fluctuation paraconductivity in sufficiently strong electric fields was studied about three decades ago in connection with the low temperature superconductors both theoretically, for the isotropic case [6,7,8], and experimentally, on thin aluminum films [9,10], with a good agreement between experiment and theory. The issue of the non-Ohmic fluctuation conductivity for a layered superconductor, a situation very much resembling the crystal structure in the HTS, has been addressed theoretically a decade ago starting from a microscopic approach [11], and more recently, in the frame of the time-dependent Ginzburg-Landau (TDGL) theory, in the Gaussian approximation [12], and in the self-consistent Hartree approach [13].…”

Section: Introductionmentioning

confidence: 94%

Depairing current and superconducting transition of YBCO at intense pulsed currents

Lang

Puica

Peruzzi

et al. 2005

phys. stat. sol. (c)

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The critical current density of a superconductor as a function of temperature and magnetic field is a key quantity for the design of superconductor applications. Tremendous efforts are currently undertaken to enhance the critical current in technical materials by improving the pinning forces. The ultimate thermodynamic limit for carrying a superconducting current is named the depairing current and usually cannot be measured directly. Our measurements are carried out using short-pulse currents with about 50 ns duration in order to avoid thermal heating and eventually destruction of the samples that result inevitably from such high dissipation. In addition, ultrathin films of YBa 2Cu3O7−x are used, patterned to microbridges to allow for an effective heat transfer into the MgO substrate. The depairing current is directly measured and is in good accordance with the values predicted by Ginzburg-Landau theory. In intense currents the critical temperature is not only shifted to lower temperatures, as seen in conventional d.c. measurements, but the shape of the transition changes significantly. The latter effect is attributed to a reduction of the fluctuation paraconductivity with increasing electric field and is compared to our recent theoretical work.

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Nonlinear Effects on the Conductivity of a Superconductor above Its Transition Temperature

Abstract: We study the conductivity

Cited by 57 publications

References 10 publications

Fluctuation conductivity in superconductors in strong electric fields

Fluctuation conductivity in superconductors in strong electric fields

Critical fluctuation conductivity in layered superconductors in a strong electric field

Depairing current and superconducting transition of YBCO at intense pulsed currents

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