Measurement of noise in the resistive state of type II superconductors

Ooijen, D.J. van; Gurp, G. J. van

doi:10.1016/0031-9163(65)90500-7

Cited by 51 publications

(16 citation statements)

References 4 publications

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“…These results are at variance with predictions of shot-noise models, where dV(t)--(vt/W)50(t) (strict equality would be obtained in the approximate rectangular-pulse model first proposed in Ref. [1]), so that ^Fand ^O should be totally correlated. Moreover, the expected ratio S^*/5V* should be much larger than that observed by a factor of 10^-10"* (depending on the sample size).…”

Section: Cyv(t)-2r^(w/l)u*^cv(r)mentioning

confidence: 39%

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Critical-current fluctuations and flux-flow noise in type-II superconductors

Plaçais¹,

Mathieu²,

Simon³

1993

Phys. Rev. Lett.

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By relying on a recent theory of transport in the mixed state and a related model of pinning in soft materials, the instantaneous critical current is introduced as a well-defined part I\ of the total constant current. This nondissipative and time-dependent I\ is assumed to be randomly distributed near the sample surface, and is described as a 2D turbulent homogeneous flow. Auto-and cross-correlation functions of both voltage and magnetic field noises are predicted and are in full agreement with experiments.PACS numbers: 74.60.Ge, 74.60Jg Flux-flow noise has been extensively studied, particularly during the 1960's and 1970's [1-6]. The spectrum and amplitude of the noise voltage dV(t), typically 10 ~^-10 "'' V/(Hz) ^/^ in the 0-10 kHz bandwidth, were regarded as significant parameters revealing the more or less irregular motion of vortex lines (VL) in the presence of pinning. The reader is referred to the excellent critical review by Clem [7]. In view of the experimental difficulties and the increasing intricacy of interpretations, this scope has been practically discarded since about 1980.It should be noted that soft samples were used, classically shaped as foils or strips perpendicular to the applied magnetic field. Low to moderate critical currents /^ are required to avoid spurious sources of noise due to excessive dissipation, such as flicker noise [7]. Therefore, at working temperatures (4.2 K [1,2,5] or close to the X point [6]), the authors had to operate at the onset of the /-K curve; in this region, where flux flow is essentially inhomogeneous along the sample [8], measurements yield unreliable results.Recently [9], we have reconsidered the problem of noise, both theoretically and experimentally. We have performed a series of experiments in superfluid helium in order to widely explore the flux-flow regime. Voltage noise, magnetic field noise around the sample, and thermal Joule noise [10] were investigated, as well as their cross correlations. By relying on a phenomenological theory of vortex motion, recently published by two of us, Mathieu and Simon (MS) [11], we were able to work out a consistent theory of noise, the principle of which is brought forward in this Letter.Roughly speaking, two mechanisms have been advanced to account for the voltage noise quantitatively. In their pioneering work, van Ooijen and van Gurp [1] assumed that flux bundles nucleated randomly at one edge and moved rigidly across the sample with constant velocity VL. This process gives rise to a time sequence of statistically independent pulses, the cutoff' frequency of the noise spectrum being related to the time of flight of bundles. This analogy with the electronic "shot noise" was attractive, but more and more adjustable parameters were introduced to fit the data; besides the flux bundle size ipb, others include the fraction of pinned vortices [2], or a distribution of subpulse times [6]. Somewhat artificially, ipb is found to be a rapidly decreasing function of current, falling off* below the flux quantum <^o [2,6]. Moreov...

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Section: Cyv(t)-2r^(w/l)u*^cv(r)mentioning

confidence: 39%

“…The surface shown in this case is the mean smoothed surface. In the perturbed layer, vortex lines are not field lines, in accordance with the London macroscopic equation(1).…”

mentioning

confidence: 79%

Critical-current fluctuations and flux-flow noise in type-II superconductors

Plaçais¹,

Mathieu²,

Simon³

1993

Phys. Rev. Lett.

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“…In such a circumstance, the distribution of the intergranular magnetic field in the interior of the superconducting specimen is determined by its intergranular features. This was the main difference of this transport method as compared with previous studies under stationary conditions of temperature and applied magnetic fields [8,9], or excitation current and applied magnetic fields [10].…”

Section: Introductionmentioning

confidence: 62%

Transport Barkhausen-like noise in uniaxially pressed Bi1.65Pb0.35Sr2Ca2Cu3O10+ ceramic samples

García-Fornaris

Govea-Alcaide

Alberteris-Campos

et al. 2010

Physica C: Superconductivity

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a b s t r a c tWe report on the detection of the transport Barkhausen-like noise (TBN) in polycrystalline samples of Bi 1.65 Pb 0.35 Sr 2 Ca 2 Cu 3 O 10+d (Bi-2223) which were subjected to different uniaxial compacting pressures. The transport Barkhausen-like noise was measured when the sample was subjected to an ac triangular-shape magnetic field (f $ 1 Hz) with maximum amplitude B max % 5.5 mT, in order to avoid the flux penetration within the superconducting grains. Analysis of the TBN signal, measured for several values of excitation current density, indicated that the applied magnetic field in which the noise signal first appears, B a (t i ), is closely related to the magnetic-flux pinning capability of the material. The combined results are consistent with the existence of three different superconducting levels within the samples: (i) the superconducting grains; (ii) the superconducting clusters; and (iii) the weak-links. We finally argue that TBN measurements constitute a powerful tool for probing features of the intergranular transport properties in polycrystalline samples of high-T c superconductors.

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“…Their results revealed that the vortices moved as rigid rods. 0953-8984/97/367593+07$19.50 c 1997 IOP Publishing Ltd As pointed out previously for the low-T c superconductors [8,9], the noise voltage is produced by a sequence of random, overlapping pulses arising from the motion of flux lines or bundles of flux lines. This type of model emphasizes the motion of the individual flux line which is driven by the Lorentz force, and provides a suitable description for the vortex motion in superconductors with strong flux pinning.…”

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confidence: 94%

Transversely diode-pumped passivelyQ-switched erbium glass laser emitter

et al. 2008

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Voltage noise of the Bi 2 Sr 2 CaCu 2 O 8+x single crystal below T c is analysed by an asymptotic power spectrum method. The low-frequency noise power, S v (T ), shows a peak at T = T p . This peak is found to be closely related to the vortex lattice melting temperature. Near the peak T = T p the power spectrum, S v (f ), exhibits a power-law fall-off, while at much lower temperatures S v (f ) dramatically deviates from the power-law behaviour, showing some broad peaks which are superposed upon a background with an exponential-law characteristic. The estimated correlation dimension of the noise data reveals that the vortex motion is highly correlated at the early stage of melting, then develops into an extended dissipative dynamic system with self-organized criticality, showing a 1/f α behaviour. The correlated motion disappears when the lattice completely melts.

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Measurement of noise in the resistive state of type II superconductors

Cited by 51 publications

References 4 publications

Critical-current fluctuations and flux-flow noise in type-II superconductors

Critical-current fluctuations and flux-flow noise in type-II superconductors

Transport Barkhausen-like noise in uniaxially pressed Bi1.65Pb0.35Sr2Ca2Cu3O10+ ceramic samples

Transversely diode-pumped passivelyQ-switched erbium glass laser emitter

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