Thickness dependence of the triplet spin-valve effect in superconductor–ferromagnet–ferromagnet heterostructures
| Autor: | Hans-Albrecht Krug von Nidda, Anatolie Sidorenko, D. Lenk, Siegfried Horn, Reinhard Tidecks, J. Kehrle, Mikhail Yu Kupriyanov, Claus Müller, R. Morari, R. G. Deminov, Lenar Tagirov, V. I. Zdravkov, G. Obermeier, Aladin Ullrich |
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| Rok vydání: | 2016 |
| Předmět: |
Materials science
Spin valve General Physics and Astronomy 02 engineering and technology lcsh:Chemical technology lcsh:Technology 01 natural sciences Full Research Paper Magnetization Condensed Matter::Superconductivity 0103 physical sciences Nanotechnology lcsh:TP1-1185 General Materials Science Singlet state Electrical and Electronic Engineering lcsh:Science 010306 general physics Superconductivity Condensed matter physics Magnetic moment lcsh:T 021001 nanoscience & nanotechnology lcsh:QC1-999 Coherence length Nanoscience superconducting spin valve Exchange bias heterostructures thin films triplet superconductivity lcsh:Q Microscopic theory 0210 nano-technology lcsh:Physics |
| Zdroj: | Beilstein Journal of Nanotechnology, Vol 7, Iss 1, Pp 957-969 (2016) Beilstein Journal of Nanotechnology |
| ISSN: | 2190-4286 |
| DOI: | 10.3762/bjnano.7.88 |
| Popis: | Background: In nanoscale layered S/F1/N/F2/AF heterostructures, the generation of a long-range, odd-in-frequency spin-projection one triplet component of superconductivity, arising at non-collinear alignment of the magnetizations of F1 and F2, exhausts the singlet state. This yields the possibility of a global minimum of the superconducting transition temperature Tc, i.e., a superconducting triplet spin-valve effect, around mutually perpendicular alignment.Results: The superconducting triplet spin valve is realized with S = Nb a singlet superconductor, F1 = Cu41Ni59 and F2 = Co ferromagnetic metals, AF = CoOx an antiferromagnetic oxide, and N = nc-Nb a normal conducting (nc) non-magnetic metal, which serves to decouple F1 and F2. The non-collinear alignment of the magnetizations is obtained by applying an external magnetic field parallel to the layers of the heterostructure and exploiting the intrinsic perpendicular easy-axis of the magnetization of the Cu41Ni59 thin film in conjunction with the exchange bias between CoOx and Co. The magnetic configurations are confirmed by superconducting quantum interference device (SQUID) magnetic moment measurements. The triplet spin-valve effect has been investigated for different layer thicknesses, dF1, of F1 and was found to decay with increasing dF1. The data is described by an empirical model and, moreover, by calculations using the microscopic theory.Conclusion: The long-range triplet component of superconducting pairing is generated from the singlet component mainly at the N/F2 interface, where the amplitude of the singlet component is suppressed exponentially with increasing distance dF1. The decay length of the empirical model is found to be comparable to twice the electron mean free path of F1 and, thus, to the decay length of the singlet component in F1. Moreover, the obtained data is in qualitative agreement with the microscopic theory, which, however, predicts a (not investigated) breakdown of the triplet spin-valve effect for dF1 smaller than 0.3 to 0.4 times the magnetic coherence length, ξF1. |
| Databáze: | OpenAIRE |
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