The effect of fluctuations on the electrical transport behaviour in YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-x</sub>
S Vitta; S A Alterovitz; M A Stan; S Vitta; Lewis Res. Center, NASA, Cleveland, OH, USA; S A Alterovitz; Lewis Res. Center, NASA, Cleveland, OH, USA; M A Stan; Lewis Res. Center, NASA, Cleveland, OH, USA
Журнал:
Journal of Physics: Condensed Matter
Дата:
1992-09-28
Аннотация:
The excess conductivity behaviour of highly oriented YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-x</sub> thin films prepared by both coevaporation and laser ablation has been studied in detail in the reduced-temperature range 9*10<sup>-4</sup><t<1. The excess conductivity in all the films studied was found to diverge sharply near T<sub>c</sub>, in agreement with the conventional mean-field theory. However, the detailed temperature dependence could not be fitted to either the power-law or the logarithmic functional forms as predicted by the theory. The excess conductivity of all the films was found to be exponentially dependent on the temperature over nearly three decades for 9*10<sup>-4</sup><t<10<sup>-1</sup>, in contradiction to the mean-field theory.
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