Izvorni znanstveni članak
Irreversibility line of Bi2223/Ag tape in high magnetic fields
Ivica Kušević
; Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia
Emil Babić
; Department of Physics, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia
John R. Cooper
; Interdisciplinary Research Centre in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 OHE, United Kingdom
Wei Guo Wang
; Centre for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2522, Australia
Hua Kun Liu
; Centre for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2522, Australia
Shi Xue Dou
; Centre for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2522, Australia
Sažetak
The magnetoresistance of a (Bi,Pb)2Sr2Ca2Cu3O10+y Ag sheathed tape was measured in the temperature range 15 K ≤ T ≤ 120 K and magnetic field B ≤ 15 T applied perpendicular to the broader surface of tape. Throughout the explored field range, the onset of resistivity shows Arrhenius behaviour ρ ∝ exp(−U∗(1 − T /Tcs)/kBT B0.5) where U∗ is the sample dependent constant, and Tcs is the temperature somewhat higher than the temperature of the resistivity onset. The observed resistance variation can be attributed to a thermally activated flux flow in a highly viscous vortex-liquid regime characterized by a plastic deformation of vortices. Experimentally determined resistive irreversibility line Birr vs. Tirr follows the power-law dependence Birr(Tirr) ∝ (Tcs/Tirr − 1)2 which can be derived from the exponential behaviour of resistivity. Our Birr(Tirr) data can also be fitted by the combination of the Josephson coupling model and depinning of pancake vortices. This fit provides very reasonable values for Bc2, Bc1, Bc, ξab and λab of Bi2223 compound, and removes the unphysical divergence of Birr(T → 0)
resulting from the above power-law fit.
Ključne riječi
(Bi; Pb)2Sr2Ca2Cu3O10+yAg sheathed tape; magnetoresistance; viscous vortex-liquid regime; resistive irreversibility line
Hrčak ID:
301024
URI
Datum izdavanja:
3.10.1999.
Posjeta: 192 *