TY - JOUR
T1 - Microstructure and fluctuation-induced conductivity analysis of Bi2 Sr2 CaCu2 O8+δ (Bi-2212) nanowire fabrics
AU - Koblischka, Michael Rudolf
AU - Koblischka-Veneva, Anjela
AU - Zeng, Xianlin
AU - Hannachi, Essia
AU - Slimani, Yassine
N1 - Funding Information:
Funding: This work is subsidized by DFG project Ko2323/10, which is gratefully acknowledged.
Publisher Copyright:
© 2020 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2020/11
Y1 - 2020/11
N2 - Resistance measurements were performed on Bi2 Sr2 CaCu2 O8+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.
AB - Resistance measurements were performed on Bi2 Sr2 CaCu2 O8+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.
KW - Bi-2212 superconductor
KW - Electrospinning
KW - Fluctuation-induced conductivity
KW - Microstructure
KW - Nanofiber fabrics
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U2 - 10.3390/cryst10110986
DO - 10.3390/cryst10110986
M3 - Article
AN - SCOPUS:85094826239
VL - 10
SP - 1
EP - 18
JO - Crystals
JF - Crystals
SN - 2073-4352
IS - 11
M1 - 986
ER -