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

Abstract

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.

Size-Dependent Magnetic Properties of Single-Crystalline Multiferroic BiFeO3 Nanoparticles

“…By contrast, the lack of an appreciable hysteresis in SQUID data was correlated with an increased intensity of the 136 cm -1 Raman peak for BiFeO 3 samples larger than 95 nm (Figure f and g). We also note by means of comparison that the Raman spectrum of bulk BiFeO 3 samples, shown in Figure h, is in good agreement with that of previously reported data 5 Raman spectra of as-prepared BiFeO 3 nanoparticles with typical dimensions of (a) 14 nm, (b) 41 nm, (c) 51 nm, (d) 75 nm, (e) 95 nm, (f) 245 nm, and (g) 342 nm, respectively, as well as of the bulk (h).…”

“…We also note by means of comparison that the Raman spectrum of bulk BiFeO 3 samples, shown in Figure 5h, is in good agreement with that of previously reported data. 45 In summary, this is the first reported study of the synthesis and characterization of pure-phase, substrate-free, and relatively strain-free (as compared with epitaxially grown films) 46 single-crystalline BiFeO 3 nanoparticle specimens. Our nanoparticles exhibit size-dependent magnetic behavior wherein the particles are analogous to incomplete magnetic supercells that retain a net magnetic moment.…”

Estimation of the Josephson critical current of a single grain: percolation model of the resistive transition

“…[1][2][3][4] as reviews) are f cont p E0:17 for continuum and f latt p E0:20 for dense lattices. These results were recently corroborated experimentally [5]. We accept f p ¼ f cont p E0:17 for our sample.…”

Characteristics of Plasma Sprayed BSCCO Superconductor Coatings with Annealing Time After Partial Melt Process

“…1911년 네델란드 과학자 온네스(Onnes)에 의해 처음으 로 초전도 현상(superconductivity)이 발견된 이래 초전도 체에 대한 이해와 응용을 위해 다양한 이론과 연구개발 이 이루어져 왔다. 특히 Maeda 등이 발견한 Bi-계 고 온초전도체 [1][2]…”