Current noise in HTC polycrystalline superconductors a comparison between experiments and different types of percolation models

Cattaneo, L.; Celasco, M.; Masoero, A.; Mazzetti, P.; Puica, I.; Stepanescu, A.

doi:10.1016/0921-4534(96)00322-x

Cited by 24 publications

(17 citation statements)

References 29 publications

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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: 79%

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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Section: Introductionmentioning

confidence: 79%

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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“…Alternative models to explain the noise produced in high Tc superconductors, both in stationary or non stationary conditions, are based on density fluctuations of fluxoids, moving in a matrix of pinning points [3][4][5]. According to these models, the noise produced during the transition is expected to be not much different from the l/f noise detected in stationary condition, and its intensity to be dependent on the fact that the resistive transition is produced by slowly varying the temperature in the absence of a magnetic field, or by producing the transition at constant temperature by applying a variable magnetic field.…”

Section: Discussionmentioning

confidence: 99%

Analysis Of Current Noise During The Resistive Transition Of MgB[sub 2] Thin Films Produced By The Application Of An External Magnetic Field

Andreoli¹,

Mazzetti²,

Stepanescu³

et al. 2009

AIP Conference Proceedings

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Noise analysis of carbon nanotube field effect transistors irradiated by electron beamShot noise analysis in quasi one-dimensional Field Effect Transistors AIP Conf.Abstract. The excess noise observed during the resistive transition of a superconducting material can be used to shed light on the microscopic processes underlying the transition itself. In a previous paper [1] it has been proposed a model to explain the large noise observed during the resistive transition of MgB2 superconducting films, obtained by slowly increasing the specimen temperature across its critical value when a d.c. bias current is applied. The amplitude and frequency behaviour of the noise power spectrum, simulated with this model, are in good agreement with the experimental data. The model is based on the onset of correlated transition of large sets of grains forming resistive layers through the specimen cross section, giving rise to resistance steps. It is assumed that these events produce the large noise, of \lf type in the low frequency range, observed in the experiments. To compare this model with alternative ones, based on dissipative effects produced by fluxoid dynamics, new results, obtained by producing the transition by varying an applied magnetic field, are reported in this paper. The fact that the transition noise remains practically unchanged, even if the fluxoid density is much increased by the magnetic field, suggests that the transition mechanism proposed in the described model is more appropriate than the one based on fluxoid dynamics.

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“…In addition to this noise component there is also a 1/f component which has a different origin, as pointed out in the previous section. According to the model briefly described above, the 1/f 2 spectral component is generated by a series of random steps of the electrical resistance during its increase or decrease by effect of a varying current or field, while the 1/f component may be generated by resistance fluctuations due to reversible transitions between superconductive and resistive state of those weak links which are near to a critical state, induced by temperature fluctuations [12,13,14,15]. In a different situation, when weak links do not play an important role, the noise may be predominantly generated by fluxoids motion.…”

Section: Resultsmentioning

confidence: 99%

Current noise in high Tc granular superconductors under non-stationary conditions of current and magnetic field

et al. 2003

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We present a set of experimental results concerning the power spectrum of current noise, detected on a granular high Tc superconductor submitted either to a slowly varying magnetic field or to a varying current intensity. Experiments were performed on a YBCO specimen suitably treated in order to weaken the weak links without affecting the oxygen content of grains. The weakening of the intergrain region allowed the use of very small magnetic fields and currents to induce the resistive transition of the specimen and to observe current noise. The induced noise is of the 1/f 2 type and will be interpreted in terms of two different models. One of the model is based on the enhancement of the noise due to the clustering of the resistive transition of the weak links, produced by correlation effects related to the strong nonlinearity of their Josephson type I-V characteristics. This model has been the object of a computer simulation based on a 3D-network of Josephson-like elements and seems suitable to explain the noise produced by current variation. The second model explains the excess noise as produced by discontinuous penetration of the magnetic flux inside the intergrain region. This discontinuity is related to the field screening effect of rings made of several superconducting weak links connecting different grains, which are alternatively broken and restored by the current induced during flux variation, and seems suitable to explain the larger noise produced by a varying magnetic field.

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Current noise in HTC polycrystalline superconductors a comparison between experiments and different types of percolation models

Cited by 24 publications

References 29 publications

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

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

Analysis Of Current Noise During The Resistive Transition Of MgB[sub 2] Thin Films Produced By The Application Of An External Magnetic Field

Current noise in high Tc granular superconductors under non-stationary conditions of current and magnetic field

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