ISSN:
1572-9605
Keywords:
Superconductivity
;
Ag composites
;
percolation
;
granularity
;
weak-link resistivity
Source:
Springer Online Journal Archives 1860-2000
Topics:
Electrical Engineering, Measurement and Control Technology
,
Physics
Notes:
Abstract Temperature-dependent electrical resistivity in a set of YBa2Cu3O7−x /Ag composites, all prepared under an identical sintering schedule, is analyzed to extract granularity information. The weak-link resistivity ρ wl across the grain boundaries and the percolation factor α arising due to current frustration caused by misalignment of anisotropic grains and sample defects such as voids and cracks are estimated from the residual resistivity ρ0 and the temperature coefficient of resistivity dρ/dT. Variation of these parameters with Ag vol.% quantifying the extent of granularity indicates that granularity in the composites decreases and their electrical characteristics tend to be identical to that of Ag-free YBa2Cu3O7−x single crystals and epitaxial thin films as Ag vol.% approaches a value where onset of current percolation occurs through Ag channels. The increased α and decreased ρ wl observed at higher Ag vol.% explains the larger grains in the composites with narrow size distribution.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1022609432697
Permalink
