Nematic versus ferromagnetic spin filtering of triplet Cooper pairs in superconducting spintronics
| Autor: | A. F. Volkov, Konstantin B. Efetov, Andreas Moor |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Superconductivity
Physics Josephson effect Condensed matter physics Spintronics Condensed Matter - Superconductivity FOS: Physical sciences Condensed Matter Physics Electronic Optical and Magnetic Materials Superconductivity (cond-mat.supr-con) Magnetization Ferromagnetism Liquid crystal Condensed Matter::Superconductivity Singlet state Cooper pair |
| DOI: | 10.48550/arxiv.1508.06665 |
| Popis: | We consider two types of magnetic Josephson junctions~(JJ). They are formed by two singlet superconductors~S and magnetic layers between them so that the JJ is a heterostructure of the S$_{\text{m}}$/n/S$_{\text{m}}$ type, where~S$_{\text{m}}$ includes two magnetic layers with non-collinear magnetization vectors. One layer is represented by a weak ferromagnet and another one---the spin filter---is either conducting strong ferromagnet (nematic or N\nobreakdash-type JJ) or magnetic tunnel barrier with spin-dependent transparency (magnetic or M\nobreakdash-type JJ). Due to spin filtering only fully polarized triplet component penetrates the normal n~wire and provides the Josephson coupling between the superconductors~S. Although both filters let to pass triplet Cooper pairs with total spin~$\mathbf{S}$ parallel to the filter axes, the behavior of nematic and magnetic JJs is completely different. Whereas in the nematic case the charge and spin currents,~$I_{\text{Q}}$ and~$I_{\text{sp}}$, do not depend on mutual orientation of the filter axes, both currents vanish in magnetic~JJ in case of antiparallel filter axes, and change sign under reversing the filter direction. The obtained expressions for~$I_{\text{Q}}$ and~$I_{\text{sp}}$ show clearly a duality between the superconducting phase~$\varphi$ and the angle~$\alpha$ between the exchange fields in the weak magnetic layers. Comment: published version |
| Databáze: | OpenAIRE |
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