Temperature induced crossover between 0 and pi states in S/F/S junctions
| Autor: | Sellier, Hermann, Baraduc, Claire, Lefloch, Francois, Calemczuk, Roberto |
|---|---|
| Přispěvatelé: | Département de Recherche Fondamentale sur la Matière Condensée (DRFMC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA) |
| Jazyk: | angličtina |
| Rok vydání: | 2003 |
| Předmět: |
[PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con]
Condensed Matter::Superconductivity Josephson junction S/F/S junction pi junction Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Andreev bound state 74.50.+r 74.45.+c [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall] |
| Zdroj: | Physical Review B: Condensed Matter and Materials Physics (1998-2015) Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2003, 68, pp.054531 Physical Review B: Condensed Matter and Materials Physics (1998-2015), American Physical Society, 2003, 68, pp.054531 |
| ISSN: | 1098-0121 1550-235X |
| Popis: | Ferromagnetic Josephson junctions can show at equilibrium a pi phase difference between the superconducting electrodes. We explain this pi state in an original way by a modified spectrum of Andreev bound states shifted by the exchange energy. A simplified expression for the spectral supercurrent density is calculated and the non-monotonic temperature dependence of the critical current is discussed. This model accounts for the cancellation of the critical current with temperature observed in a small range of barrier thickness in our Nb/Cu52Ni48/Nb junctions. This cancellation corresponds to an inversion of the supercurrent and to a ground state crossover from a 0 state to a pi state. This transition is caused both by the thermal distribution of quasi-particles and by the temperature dependence of the exchange energy. The experimental curves are well reproduced by our theoretical expression except for the very small amplitude of the supercurrent attributed to a large spin-flip scattering. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|