Publication Date:
2014-09-13
Description:
Silver (Ag) nanoparticles were added into (Cu 0.5 Tl 0.5 )Ba 2 Ca 2 Cu 3 O 10−δ (CuTl-1223) high T c superconducting matrix to get (Ag) x /CuTl-1223, x = 0, 0.5, 1.0, 2.0, and 4 wt. %, nano-superconductor composites. The activation energy {U (eV)} and zero resistivity critical temperature {T c (0)} were increased with increasing contents of Ag nanoparticles in (CuTl-1223) phase up to x = 2.0 wt. %. The increase of activation energy is most probably due to interaction of carriers with the metallic Ag nanoparticles present at grain boundaries of the host CuTl-1223 superconducting matrix. The systematic increase in T c (0) and gradual decrease in normal state resistivity {ρ 300 K (Ω cm)} may be due to improved inter-grains coupling by filling up the voids and pores with the inclusion of metallic Ag nanoparticles at the grain-boundaries. There are two possible mechanisms associated with the inclusion of Ag nanoparticles, one is the formation of non-superconducting regions causing the increase of activation energy and other (dominating) is the improved inter-grains connectivity promoting T c (0). The microscopic parameters (i.e., zero temperature coherence length along c-axis {ξ c (0)}, inter-layer coupling (J), inter-grain coupling (α), etc.) deduced from the fluctuation induced conductivity analysis reasonably explained the experimental findings.
Print ISSN:
0021-8979
Electronic ISSN:
1089-7550
Topics:
Physics
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