| Autor: |
J. Joffrin, M. Stenger, S. Friemel, J.-Y. Prieur, S. Baumhoff |
| Rok vydání: |
1999 |
| Předmět: |
|
| Zdroj: |
Solid State Communications. 110:115-119 |
| ISSN: |
0038-1098 |
| Popis: |
We report electrical transport measurements of thin YBCO-films with three different oxygen contents in the mixed state, with a magnetic field applied perpendicular to the CuO2 layers. We have analysed our resistivity data in the framework of two models: the thermally activated flux-flow model and the vortex-glass theory. The thermally activated flux-flow model yields an interesting result concerning the dependence of the activation barriers on magnetic field. For a highly oxygenated film ( δ=0.08 ), the activation barrier decreases as the inverse of the square root of the magnetic field. For the two films with lower oxygen contents studied ( δ=0.24 and δ=0.31 ), this dependence is found to be logarithmic. The vortex-glass theory yields the combination ν(z+2−d) of the scaling exponents ν and z for our different samples. The combination value does not change with the oxygen content and agrees with theory and experimental results of other groups. We cannot exclude either of these two models on the basis of our data. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect