Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 4: Superconductivity: Qubits I
TT 4.11: Vortrag
Montag, 12. März 2018, 12:15–12:30, H 2053
Superconducting spin valves based on nontrivial magnets — •Nataliya Pugach1,2, Mikhail Safonchik3, and Dennis Heim4 — 1Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Leninskie Gory1(2), 119991, Moscow, Russia — 2National Research University Higher School of Economics, 101000, Moscow, Russia — 3A. F. Ioffe Physical-Technical Institute, RU-194021 St. Petersburg, Russia — 4University Ulm, Germany
Superconducting spintronics has emerged in the last decade as a promising new field that seeks to open a new dimension for nanoelectronics by utilizing the internal spin structure of the superconducting Cooper pair as a new degree of freedom. Currently, the discipline finds itself at the crossroads for developing first-generation devices. Among the basic units of superconducting spintronics are the so-called superconducting spin valves. These are nanodevices in which the superconducting current is controlled through the spin degree by changing the magnetization of magnetic elements.
We propose a superconducting spin-triplet valve, which consists of a superconductor and an itinerant magnetic material, with the magnet showing an intrinsic non-collinear order characterized by a wave vector that may be aligned in a few equivalent preferred directions under the control of a weak external magnetic field. Re-orienting the spiral direction allows one to controllably modify long-range spin-triplet superconducting correlations, leading to spin-valve switching behavior. Our results indicate that the spin-valve effect may be noticeable [1,2]. This bilayer may be used as a magnetic memory element for cryogenic nanoelectronics. Josephson superconducting span valve based on the same principle is also considered.
Such spin valves have the following advantages in comparison to superconducting spin valves proposed previously: (i) it contains only one magnetic layer, which may be more easily fabricated and controlled; (ii) its ground states are separated by a potential barrier, which solves the “half-select” problem of the addressed switch of memory elements.
The work was supported by joint Russian-Greek projects RFMEFI61717X0001 and T4ΔPΩ-00031 “Experimental and theoretical studies of physical properties of low-dimensional quantum nanoelectronic systems”.
[1] N. G. Pugach, M. Safonchik, T. Champel, M. E. Zhitomirsky, E. Lahderanta, M. Eschrig, and C. Lacroix. Appl. Phys. Lett. 111, 162601 (2017).
[2] N. G. Pugach, M. Safonchik, JETP Lett. 107 (5), (2018) (accepted).