Tunnel spin injection and the conductivity of ferromagnet-superconductor heterostructures with zero bias
| Autor: | A. A. Krakovny, M. V. Dyakin, Yu. V. Kudryavtsev, Yu. V. Shlapak, I. V. Korotash, E. M. Rudenko |
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| Rok vydání: | 2011 |
| Předmět: |
Superconductivity
Materials science Physics and Astronomy (miscellaneous) Spin polarization Condensed matter physics General Physics and Astronomy Electron Conductivity Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Condensed Matter::Materials Science Ferromagnetism Electrical resistance and conductance Tunnel junction Condensed Matter::Superconductivity Condensed Matter::Strongly Correlated Electrons Quantum tunnelling |
| Zdroj: | Low Temperature Physics. 37:489-495 |
| ISSN: | 1090-6517 1063-777X |
| DOI: | 10.1063/1.3620864 |
| Popis: | The giant spin blocking of tunnel currents discovered by us (Low. Temp. Phys. 36, 186 (2010)) is investigated theoretically and experimentally in ferromagnet F (Co2CrAl)- insulator I- superconductor S (Pb) heterostructures with a wide range of specific resistances (10−7–10−4 Ω · cm2). The magnitude of this effect is found to depend on the specific resistance of the junction in the normal state and on recombination spin depolarization. A theoretical model which provides an adequate description of the tunnelling of spin-polarized electrons in F-I-S junctions is proposed. It is found that the normalized conductivity σFS of an F-I-S tunnel junction can be considerably lower than the fundamental normalized conductivity σNS of an N-I-S junction (where N is a normal metal). The proposed model is used to estimate the degree of spin polarization p of films of the ferromagnetic semimetal Co2CrAl (Heusler alloy) with B2- and L21-type crystal structures, which is close to 1 (p ≈ 0.97). The temperature dependence σFS(... |
| Databáze: | OpenAIRE |
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