Multiple Andreev reflections spectroscopy of two-gap 1111- and 11 Fe-based superconductors
| Autor: | Ponomarev, Ya. G., Kuzmichev, S. A., Kuzmicheva, T. E., Mikheev, M. G., Sudakova, M. V., Tchesnokov, S. N., Volkova, O. S., Vasiliev, A. N., Pudalov, V. M., Sadakov, A. V., Usol'tsev, A. S., Wolf, Th., Khlybov, E. P. |
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| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | J. Supercond. Nov. Magn. 26, 2867-2871 (2013) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1007/s10948-013-2264-7 |
| Popis: | Using the "break-junction" technique we prepared and studied superconductor - constriction - superconductor nanocontacts in polycrystalline samples of Fe-based superconductors CeO$_{0.88}$F$_{0.12}$FeAs (Ce-1111; $T_C^{\rm bulk} = 41 \pm 1 K$), LaO$_{0.9}$F$_{0.1}$FeAs (La-1111; $T_C^{\rm bulk} = 28 \pm 1 K$), and FeSe ($T_C^{\rm bulk} = 12 \pm 1 K$). We detected two subharmonic gap structures related with multiple Andreev reflections, indicating the presence of two superconducting gaps with the BCS-ratios $2\Delta_L/k_BT_C = 4.2 \div 5.9$ and $2\Delta_S/k_BT_C\sim 1 \ll 3.52$, respectively. Temperature dependences of the two gaps $\Delta_{L,S}(T)$ in FeSe indicate a $k$-space proximity effect between two superconducting condensates. For the studied iron-based superconductors we found a linear relation between the gap $\Delta_L$ and magnetic resonance energy, $E_{\rm res} \approx 2\Delta_L$. Comment: 6 pages, 7 figures. Proceedings of FPS'11 conference |
| Databáze: | arXiv |
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