Superfluid density of superconductor-ferromagnet bilayers
| Autor: | Lemberger, Thomas R., Hetel, Iulian, Hauser, Adam J., Yang, F. Y. |
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| Rok vydání: | 2007 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1063/1.2832318 |
| Popis: | We report the first measurements of the effective superfluid density n_S(T) \propto \lambda^{-2}(T) of Superconductor-Ferromagnet (SC/FM) bilayers, where \lambda is the effective magnetic field penetration depth. Thin Nb/Ni bilayers were sputtered in ultrahigh vacuum in quick succession onto oxidized Si substrates. Nb layers are 102 A thick for all samples, while Ni thicknesses vary from 0 to 100 A. T_C determined from \lambda^{-2}(T) decreases rapidly as Ni thickness d_Ni increases from zero to 15 A, then it has a shallow minimum at d_Ni \approx 25 A. \lambda^{-2}(0) behaves similarly, but has a minimum several times deeper. In fact, \lambda^{-2}(0) continues to increase with increasing Ni thickness long after T_C has stopped changing. We argue that this indicates a substantial superfluid density inside the ferromagnetic Ni films. Comment: 13 pages, 2 figures, MMM 2007 proceedings |
| Databáze: | arXiv |
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