Fluctuation conductivity analysis on the Bi‐based superconductors processed under same conditions

Azzouz, F. Ben; Zouaoui, M.; Annabi, Mohamed; Salem, M. Ben

doi:10.1002/pssc.200567027

Cited by 26 publications

(8 citation statements)

References 11 publications

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“…The value of d (= effective length in the direction perpendicular to the current flow defining the effective layer thickness of the 2D-system) with 11.6 nm is smaller than that obtained in Reference [65] with 19 nm (polycrystalline Bi-2212 samples) and for Bi-2212 single crystals [62]. This may point to a squeezing of the Cu-O-layers, which is understandable when regarding the large surface contribution in the present nanometer-sized fibers (see also Figure S4 in the Supplementary Materials).…”

Section: Discussioncontrasting

confidence: 62%

“…Several types of Bi-2212 samples were already analyzed by means of excess conductivity/fluctuation-induced conductivity in the literature. This comprises single crystals [62] polycrystalline bulks [63][64][65], polycrystalline Bi-2212 doped with Ni, La [66][67][68], and Bi-2212 thin films [69]. Several authors found the missing 1D fluctuation regime in their Bi-2212 samples, and a similar observation was made when studying the Y-358 compound [70].…”

Section: Discussionmentioning

confidence: 68%

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Microstructure and Fluctuation-Induced Conductivity Analysis of Bi2Sr2CaCu2O8+δ (Bi-2212) Nanowire Fabrics

et al. 2020

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Resistance measurements were performed on Bi2Sr2CaCu2O8+δ (Bi-2212) fabric-like nanowire networks or nanofiber mats in the temperature interval 3 K ≤T≤ 300 K. The nanowire fabrics were prepared by means of electrospinning, and consist of long (up to 100 μm) individual nanowires with a mean diameter of 250 nm. The microstructure of the nanowire network fiber mats and of the individual nanowires was thoroughly characterized by electron microscopy showing that the nanowires can be as thin as a single Bi-2212 grain. The polycrystalline nanowires are found to have a texture in the direction of the original polymer nanowire. The overall structure of the nanofiber mats is characterized by numerous interconnects among the nanowires, which enable current flow across the whole sample. The fluctuation-induced conductivity (excess conductivity) above the superconducting transition temperature, Tc, was analyzed using the Aslamzov-Larkin model. Four distinct fluctuation regimes (short-wave, two-dimensional, three-dimensional and critical fluctuation regimes) could be identified in the Bi-2212 nanowire fabric samples. These regimes in such nanowire network samples are discussed in detail for the first time. Based on this analysis, we determine several superconducting parameters from the resistance data.

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Section: Discussioncontrasting

confidence: 62%

Section: Discussionmentioning

confidence: 68%

Microstructure and Fluctuation-Induced Conductivity Analysis of Bi2Sr2CaCu2O8+δ (Bi-2212) Nanowire Fabrics

et al. 2020

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“…The value of the proportionality coefficient K in the above equations is 0.12 [22]. By using N G for Cu 0.…”

Section: Resultsmentioning

confidence: 98%

Enhancement of Inter-plane Coupling and Superconductivity in Cu0.5Tl0.5Ba2(Ca3−yM y )Cu4O12−δ (M = 0, Pr, Y, Er, Gd; y = 0.02) Samples

Khan

Ashraf

Safeer

2016

J Supercond Nov Magn

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Cu 0.5 Tl 0.5 Ba 2 (Ca 3−y M y )Cu 4 O 12−δ (M=0, Pr, Y, Er, Gd; y=0.02) samples are synthesized at normal pressure to see the effect of M +3 elements doping in enhancing the inter-plane coupling of Cu 0.5 Tl 0.5 Ba 2 (Ca 3−y M y )Cu 4 O 12−δ superconductors. These samples have shown the tetragonal crystal structure in which the axis lengths increase with doping of rare-earth impurities. In the resistivity measurements, these samples have shown metallic variations of resistivity from room temperature down to the onset of superconductivity. The onset of superconductivity, the zero resistivity critical temperature, and the magnitude of diamagnetism are suppressed with the doping of rare-earth impurities at Ca sites. The excess conductivity analysis has shown suppression in the onset temperature of 3D and 2D Lawrence-Doniach (LD) conductivity regimes. The coherence length along the c-axis (ξ c(0) ), the inter-layer coupling (J ), and the Fermi velocity (V F ) of the carriers are suppressed with Y doping, whereas the values of these parameters increase with the doping of Er and Gd. However, the values of B c0 (T ), B c1 (T ), and J c (0) are suppressed with the doping of Y, Er, and Gd. Moreover, the values of magnetic field penetration depth (λ pd ) and the Ginzburg-Landau (GL) parameter κ increase with the doping of rare-earth elements. Since the λ pd is related inversely to the density of mobile carriers in the conducting CuO 2 planes, the increase in values of these parameters indicates that the density of mobile carriers is suppressed in the conducting planes with the doping of rare-earth elements. These studies stress the pivotal role of mobile charge carriers in the mechanism of high-T c superconductivity and have shown that M +3 rareearth elements develop some localization of the carriers in their neighborhood, thereby suppressing the values of essential superconductivity parameters.Keywords Cu 0.5 Tl 0.5 Ba 2 (Ca 3−y M y )Cu 4 O 12−δ (M = 0, Pr, Y, Er, Gd, y = 0.02) superconductors · Decoupling of CuO 2 planes · Enhanced flux pinning · Longer coherence length

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“…[21][22][23] These two theories AL and LD are directly contributing to the excess conductivity which help us to study the dimensionality of fluctuations of superconductivity.…”

Section: Theoretical Models For Analysis Of Experimental Datamentioning

confidence: 99%

Effect of CuO2 planes on the structural and superconducting transport properties of [CuTl − 12(n − 1)n;n = 2,3,4] superconductor family

Muzaffar

Khan

2016

Int. J. Mod. Phys. B

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Cu 0.5 Tl 0.5 Ba 2 Ca n−1 CunO 2n+4−δ (n = 2, 3, 4) superconducting bulk samples have been synthesized by using two-step solid state reaction method. We investigated the effects of CuO 2 planes on the structural and superconducting transport properties of [CuTl-12(n−1)n; n = 2, 3, 4] superconducting family. These samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) absorption spectroscopy and DC-resistivity (ρ) measurements. These samples are c-axis length oriented and have shown orthorhombic crystal structure. All the samples have shown metallic variations of resistivity from room temperature down to onset of superconductivity. The zero resistivity critical temperature Tc(R = 0) increases with the increase in superconducting planes and normal state resistivity systematically decreases, which show the density of inadvertent defects decreases in the final compound. The apical oxygen phonon modes are hardened as observed in the FTIR absorption measurements. The intrinsic microscopic superconducting parameters, such as the cross-over temperatures, coherence length along c-axis (ξ c(0) ) at 0 K, inter-layer coupling (J), inter-grain coupling (α) and fermi velocity (V F ), were extracted from the fluctuation-induced conductivity (FIC) analysis. FIC analysis also showed the improvement in superconductivity with the increase in CuO 2 planes.

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Fluctuation conductivity analysis on the Bi‐based superconductors processed under same conditions

Cited by 26 publications

References 11 publications

Microstructure and Fluctuation-Induced Conductivity Analysis of Bi2Sr2CaCu2O8+δ (Bi-2212) Nanowire Fabrics

Microstructure and Fluctuation-Induced Conductivity Analysis of Bi2Sr2CaCu2O8+δ (Bi-2212) Nanowire Fabrics

Enhancement of Inter-plane Coupling and Superconductivity in Cu0.5Tl0.5Ba2(Ca3−yM y )Cu4O12−δ (M = 0, Pr, Y, Er, Gd; y = 0.02) Samples

Effect of CuO2 planes on the structural and superconducting transport properties of [CuTl − 12(n − 1)n;n = 2,3,4] superconductor family

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