Resistance versus temperature model for porous multiphased superconducting materials and associated parametrization method for the experimental data

Grachev, V.; Badèche, T.; Bettahi, A.; Marfaing, J.; Boulesteix, C.

doi:10.1016/0921-4534(94)90392-1

Cited by 7 publications

(5 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For 30% and even for 20% (cf figure 4), the first drop in the resistance is observed at a temperature between 90 and 110 K and the second one between 40 and 60 K, leading to a zero resistance at about 40 K. Both drops are due to the Bi-2223 and Bi-2212 phases (more or less defined), respectively, the latter appearing by decomposition of the Bi-2223 phase (which could probably be avoided or at least greatly diminished in the future). The content of Bi-2223 and Bi-2212 can be estimated by using one of the existing percolation methods to determine the concentrations of the different superconducting phases [21,22] (for more information, see also [23,24]). It must be noted that these computational methods used to model the composite consider a mixture of superconducting (or conducting) and insulating phases made of identical spheres.…”

Section: R(t ) Curves For Several Nominal Concentrations Of Bi-2223mentioning

confidence: 99%

Superconductive percolation in Bi-based superconductor/Bi-based insulator composites: case of Bi-2223/Bi-2310 and Bi-2212/BiFeO₃

Nadifi¹,

Ouali²,

Grigorescu³

et al. 2000

Supercond. Sci. Technol.

View full text Add to dashboard Cite

Preparation of Bi-2223/Bi-2310 and Bi-2212/BiFeO 3 composites has been performed so as to obtain some active composites where the superconductive properties of Bi-2223 or Bi-2212 can be modified using a property of the insulating phase. In both cases superconductive percolation was obtained, but only in the case of a Bi-2223 (or Bi-2212)/Bi-2310 composite was no (or very weak) chemical reaction observed during sintering. Since the superconductive percolation threshold was obtained in this case for a concentration of Bi-2223 or Bi-2212 lower than 20%, a special composite model had to be considered. The Bi-2212/BiFeO 3 system is very interesting due to the ferroic properties of BiFeO 3 . Superconductive percolation was achieved with this mixture too, but with more difficulties because of a chemical reaction occurring between the two compounds during sintering. A study of the properties of these composites has been performed and will be briefly described in what follows. The good quality of the Bi-2223(or Bi-2212)/Bi-2310 composite enables us to expect some future applications.

show abstract

Section: R(t ) Curves For Several Nominal Concentrations Of Bi-2223mentioning

confidence: 99%

Superconductive percolation in Bi-based superconductor/Bi-based insulator composites: case of Bi-2223/Bi-2310 and Bi-2212/BiFeO₃

Nadifi¹,

Ouali²,

Grigorescu³

et al. 2000

Supercond. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…It was previously shown that the real composition of (Bi, Pb)-2223 is Bi 1.6 Pb 0.4 Sr 2 Ca 2 Cu 3 O 10 [10]. The concentrations of these two phases were obtained by x-ray diffraction (XRD) measurements and were confirmed by a percolation model [10,12].…”

Section: Experimental Processmentioning

confidence: 79%

Corrosion of bismuth-based superconductor wires by some atmospheric agents

Azzouz¹,

M’chirgui²,

Salem³

et al. 2000

Supercond. Sci. Technol.

View full text Add to dashboard Cite

Superconducting wires (SWs) were previously prepared in our group by heat treatment of bismuth-based superconductor coatings on a metal core. This paper presents an analysis of the corrosion process by some atmospheric agents on the SWs. SWs with different concentrations of a (Bi, Pb)-2223 phase have been exposed to water vapour saturated air, to pure water vapour or to dry carbon dioxide. Each of these atmospheric agents was found to act differently on the SWs. However, all the studied corrosion processes present a high sensitivity to the concentration of the (Bi, Pb)-2223 phase. For a higher concentration of this phase, the SWs are less sensitive to atmospheric agents.

show abstract

“…It must be noted that the anomaly is reproducible (i) whether the temperature is increased or decreased, (ii) for two different current densities: 10 À2 and 10 À1 A/cm 2 . It is also worth noting that this crystal contained a few percent of Bi-2223, as can be easily deduced from a slight and reversible drop around 110 K. Using a previously described fitting procedure [10,11] we estimated the Bi-2223 concentration to be close to 1.5%. Other crystals did not contain any trace of Bi-2223 and presented an equally narrow, but less intense peak.…”

Section: Experimental Process and Resultsmentioning

confidence: 99%

Hole-Filling above Tc, at the Origin of the In-Plane Resistivity Anomaly in Bi-2212 Crystals

Boulesteix

Marietti

Monnereau³

et al. 2000

phys. stat. sol. (a)

Self Cite

View full text Add to dashboard Cite

We have observed a sharp peak (100%) in the in-plane resistivity r ab just above T c , in Bi-2212 crystals, in agreement with previous results from Han et al. who attributed this anomaly to the ªquasi-reentrant behaviourº already observed for polycrystalline samples. This explanation is very likely unadapted to these crystals and we propose another one related to a model we had used to fit r c T curves for Bi-2212 underdoped crystals, namely, an increase of the Fermi level (hole-filling) with decreasing temperature, above T c , probably due to a change in the Bi±O or Cu±O bonds. A previously reported c-axis lattice anomaly, occurring in the same temperature range, is most probably related to this bonding alteration.Nous avons observe Â, pour des cristaux de Bi-2212, un pic intense (100%) de re Â sistivite Â r ab (dans le plan des feuillets). Ceci est en accord avec des re Â sultats ante Â rieurs de Han et al. qui ont atttribue Â l'anomalie en question au comportement ªquasi-re Â entrantº caracte Â ristique des e Â chantillons polycristallins. Cette interpre Â tation ne nous semble pas pertinente dans le cas de nos cristaux et nous proposons une autre origine (d'apre Á s un mode Á le que nous avions utilise Â pour ajuster les courbes r c T de cristaux de Bi-2212 sous-dope Â s) base Â e sur une e Â le Â vation du niveau de Fermi lorsque la tempe Â rature de Â croõ Ãt (au-dessus de T c ). D'autres auteurs constatent par ailleurs une variation du parame Á tre de maille c, qui se produit dans la me Ã me gamme de tempe Â rature. Ces deux phe Â nome Á nes sont probablement lie Â s a Á une modification des liaisons Bi±O ou Cu±O.

show abstract

Resistance versus temperature model for porous multiphased superconducting materials and associated parametrization method for the experimental data

Cited by 7 publications

References 17 publications

Superconductive percolation in Bi-based superconductor/Bi-based insulator composites: case of Bi-2223/Bi-2310 and Bi-2212/BiFeO₃

Superconductive percolation in Bi-based superconductor/Bi-based insulator composites: case of Bi-2223/Bi-2310 and Bi-2212/BiFeO₃

Corrosion of bismuth-based superconductor wires by some atmospheric agents

Hole-Filling above Tc, at the Origin of the In-Plane Resistivity Anomaly in Bi-2212 Crystals

Contact Info

Product

Resources

About

Resistance versus temperature model for porous multiphased superconducting materials and associated parametrization method for the experimental data

Cited by 7 publications

References 17 publications

Superconductive percolation in Bi-based superconductor/Bi-based insulator composites: case of Bi-2223/Bi-2310 and Bi-2212/BiFeO3

Superconductive percolation in Bi-based superconductor/Bi-based insulator composites: case of Bi-2223/Bi-2310 and Bi-2212/BiFeO3

Corrosion of bismuth-based superconductor wires by some atmospheric agents

Hole-Filling above Tc, at the Origin of the In-Plane Resistivity Anomaly in Bi-2212 Crystals

Contact Info

Product

Resources

About

Superconductive percolation in Bi-based superconductor/Bi-based insulator composites: case of Bi-2223/Bi-2310 and Bi-2212/BiFeO₃

Superconductive percolation in Bi-based superconductor/Bi-based insulator composites: case of Bi-2223/Bi-2310 and Bi-2212/BiFeO₃