Effect of surface barriers on transport properties of Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>8</sub> single crystals using the Corbino disc configuration
S F W R Rycroft; R A Doyle; D T Fuchs; E Zeldov; R J Drost; P H Kes; T Tamegai; S Ooi; A M Campbell; W Y Liang; D T Foord
Журнал:
Superconductor Science and Technology
Дата:
1999-12-01
Аннотация:
Transport measurements have been made on Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>8</sub> single crystals in both Corbino disc and strip geometries. Pronounced differences are observed in both the resistive transition and the current-voltage characteristics in these two geometries. Surface barriers affect the behaviour of the strip and reduce the measured resistance of the vortex liquid by over two orders of magnitude with respect to the Corbino geometry. The critical current density of the Corbino disc, which reflects the true bulk critical current, is a factor of at least 20 times smaller. We conclude that the transport properties of Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>O<sub>8</sub> samples in the strip geometry are dominated by SB in both the solid and liquid vortex phases over a wide range of fields and temperatures.
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