Upper critical field and fluctuation conductivity in the critical regime of doped SmFeAsO
| Autor: | Pallecchi, I., Fanciulli, C., Tropeano, M., Palenzona, A., Ferretti, M., Malagoli, A., Martinelli, A., Sheikin, I., Putti, M., Ferdeghini, C. |
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| Rok vydání: | 2009 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 79, 104515 (2009) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.79.104515 |
| Popis: | We measure magnetotransport of F doped SmFeAsO samples up to 28T and we extract the upper critical fields, using different criteria. In order to circumvent the problem of criterion-dependence Hc2 values, we suggest a thermodynamic estimation of the upper critical field slope dHc2/dT based on the analysis of conductivity fluctuations in the critical regime. A high field slope as large as -12T/K is thus extracted for the optimally doped sample. We find evidence of a two-dimensional lowest Landau level (LLL) scaling for applied fields larger than mu_0H_LLL=8T. Finally, we estimate the coherence length values and we observe that they progressively increase with decreasing Tc. In all cases, the coherence length values along the c axis are smaller than the interplanar distance, confirming the two-dimensional nature of superconductivity in this compound. Comment: 14 pages, 4 figures, 3 tables Submitted to Phys.Rev.B |
| Databáze: | arXiv |
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