Scaling behavior of U(I)-characteristics and zero-field resistive transitions in epitaxial Bi2Sr2CaCu2O8+δ thin films

Wagner, Patrick; Hillmer, F.; Frey, Urban; Hadish, A.; Kluge, Th.; Petersen, K.; Adrian, H.

doi:10.1016/0921-4534(94)91109-6

Cited by 8 publications

(10 citation statements)

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“…Films prepared as such are also free of grain boundaries and so are most appropriate for investigations of the intrinsic properties of the Bi system. Several papers have already been published investigating the magnetic phase diagram, which contains several regimes of different behaviour [5,6], the electronic structure [7], which is crucial for the understanding of superconductivity, or the effect of pinning on the critical current, which is of great importance from the point of view of applications [8]. Investigation of the magnetic properties of the Bi system directly through magnetization measurements is in progress.…”

Section: Pole-figure Results and Discussionmentioning

confidence: 99%

“…Also, their broader lines compared with the 2212 and 2201 films, as can be seen in the θ -2θ scan of figure 1, may be the result of the presence of stacking faults. Stacking faults have often been observed in the Bi-2223 system [5] and they hamper the diffusion of oxygen into the films, so they may be the cause of oxygen inhomogeneity.…”

Section: Characterizationmentioning

confidence: 99%

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Preparation and x-ray pole-figure characterization of DC-sputtered Bi-2201, Bi-2212 and Bi-2223 thin films

Holiastou

Psyharis

Niarchos

et al. 1997

Supercond. Sci. Technol.

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Thin films of the three members of the superconducting series Bi 2 Sr 2 Ca n−1 Cu n O 2n+4 , n = 1, 2, 3, were prepared by diode sputtering. X-ray characterization shows that all the films are single phase and c-axis oriented and in addition they are epitaxially grown. The latter is found by x-ray pole-figure measurements taken with a four-circle diffractometer. These are emphasized in this work. AC susceptibility measurements show that, while the 2201 films are not superconducting until 4 K, the transition temperatures of the 2212 films are 82 K-90 K and of the 2223 films 84 K-89 K.

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Section: Pole-figure Results and Discussionmentioning

confidence: 99%

Section: Characterizationmentioning

confidence: 99%

Preparation and x-ray pole-figure characterization of DC-sputtered Bi-2201, Bi-2212 and Bi-2223 thin films

Holiastou

Psyharis

Niarchos

et al. 1997

Supercond. Sci. Technol.

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“…There is much evidence that the upper limit for j c in Bi tapes is not already reached (Cai et al 1998. Thin-film samples of Bi-2223 exhibit j c in the range of 10 9 -10 10 A m −2 at 77 K and the self-field (Wagner et al 1995) and 10 11 A m −2 at 20 K (Rössler et al 2001); the current-limiting mechanisms of the Bi tapes (exhibiting a very complex microstructure) are still not fully clear (Larbalestier et al 1999). Magneto-optical experiments revealed that the current flow percolates in the Bi tapes (see e.g.…”

Section: Bi-2212 and Bi-2223 Tapesmentioning

confidence: 99%

Magneto-optical studies of current distributions in high-T_csuperconductors

et al. 2002

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In the past few years magneto-optical flux imaging (MOI) has come to take an increasing role in the investigation and understanding of critical current densities in high-T c superconductors (HTS). This has been related to the significant progress in quantitative high-resolution magnetooptical imaging of flux distributions together with the model-independent determination of the corresponding current distributions. We review in this article the magneto-optical imaging technique and experiments on thin films, single crystals, polycrystalline bulk ceramics, tapes and melt-textured HTS materials and analyse systematically the properties determining the spatial distribution and the magnitude of the supercurrents. First of all, the current distribution is determined by the sample geometry. Due to the boundary conditions at the sample borders, the current distribution in samples of arbitrary shape splits up into domains of nearly uniform parallel current flow which are separated by current domain boundaries, where the current streamlines are sharply bent. Qualitatively, the current pattern is described by the Bean model; however, changes due to a spatially dependent electric field distribution which is induced by flux creep or flux flow have to be taken into account. For small magnetic fields, the Meissner phase coexists with pinned vortex phases and the geometry-dependent Meissner screening currents contribute to the observed current patterns. The influence of additional factors on the current domain patterns are systematically analysed: local magnetic field dependence of j c (B), current anisotropy, inhomogeneities and local transport properties of grain boundaries. We then continue to an overview of the current distribution and current-limiting factors of materials, relevant to technical applications like melt-textured samples, coated conductors and tapes. Finally, a selection of magneto-optical experiments which give direct insight into vortex pinning and depinning mechanisms are reviewed.

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“…However, Cai et al [2] have reported that critical current density for individual filaments may reach higher than 80 kA cm −2 . Furthermore, single-crystal thin films of Bi-2223 have been reported to have J c (77 K, 0 T) values of up to 10 6 A cm −2 , nearly 12 times the present best value for a single filament [3,4]. This implies that a substantial increase in the critical current density of Bi-2223/Ag tape should still be possible.…”

Section: Introductionmentioning

confidence: 71%

The effect of lead-rich phases on the microstructure and properties of (Bi, Pb)-2223/Ag tapes

Han

2007

Supercond. Sci. Technol.

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The effect of lead-rich phases on the microstructure and properties of (Bi, Pb)-2223/Ag tapes has been studied. Powders containing different types of lead-rich phases were prepared by controlling the processing parameters, including temperature, time and oxygen partial pressure. Then, monofilament (Bi, Pb)-2223/Ag tapes were fabricated using these powders. The phase compositions of the powders and tapes were analysed by x-ray diffraction and the microstructure of these tapes was observed using scanning electron microscopy. Experimental results show that the lead-rich phases in powders played an important role in the formation of the (Bi, Pb)-2223 phase, and the microstructure and the superconducting properties of (Bi, Pb)-2223/Ag tapes. The formation process of (Bi,Pb)2Sr2CaCu2Ox in tape fabricated using the powder containing Ca2PbO4 is different from a tape fabricated using the powder containing Pb3Sr2.5Bi0.5Ca2CuOy, which differs in the formation process and grain sizes of the (Bi, Pb)-2223 phase. Therefore, the critical currents of (Bi, Pb)-2223/Ag tapes containing various lead-rich phases are different. The highest critical current is obtained for tape fabricated using powder containing both Ca2PbO4 and 3321 phases.

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Scaling behavior of U(I)-characteristics and zero-field resistive transitions in epitaxial Bi2Sr2CaCu2O8+δ thin films

Cited by 8 publications

References 4 publications

Preparation and x-ray pole-figure characterization of DC-sputtered Bi-2201, Bi-2212 and Bi-2223 thin films

Preparation and x-ray pole-figure characterization of DC-sputtered Bi-2201, Bi-2212 and Bi-2223 thin films

Magneto-optical studies of current distributions in high-T_csuperconductors

The effect of lead-rich phases on the microstructure and properties of (Bi, Pb)-2223/Ag tapes

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Scaling behavior of U(I)-characteristics and zero-field resistive transitions in epitaxial Bi2Sr2CaCu2O8+δ thin films

Cited by 8 publications

References 4 publications

Preparation and x-ray pole-figure characterization of DC-sputtered Bi-2201, Bi-2212 and Bi-2223 thin films

Preparation and x-ray pole-figure characterization of DC-sputtered Bi-2201, Bi-2212 and Bi-2223 thin films

Magneto-optical studies of current distributions in high-Tcsuperconductors

The effect of lead-rich phases on the microstructure and properties of (Bi, Pb)-2223/Ag tapes

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Magneto-optical studies of current distributions in high-T_csuperconductors