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MEMORY EFFECT IN SUPERCONDUCTOR/FERROMAGNET NANOSTRUCTURES Co/CoOx/CuNi/Nb/CuNiтезисы доклада
- Авторы: Morari R., Zdravkov V.I., Obermeier G., Lenk D., Seidov Z., Krug von Nidda H.A., Müller C., Kupriyanov M.Yu, Sidorenko A.S., Horn S., Tidecks R., Tagirov L.R.
- Сборник: Moscow International Symposium on Magnetism (MISM), 29 June – 3 July 2014, Moscow Book of Abstracts
- Тезисы
- Год издания: 2014
- Место издания: PrintLETO.ru Moscow
- Первая страница: 898
- Аннотация: The theory of superconductor-ferromagnet (S-F) heterostructures with two and more ferromagnetic layers predicts generation of long-range, odd-in-frequency triplet pairing at non-collinear alignment of magnetizations of the F-layers ([1] and references therein). Based on ideas of the superconducting triplet spin-valve [2,3] we observed switching of the Co/CoOx/Cu41Ni59/Nb/Cu41Ni59 proximity type heterostructures between normal and (almost) superconducting states [4]. The Co/CoOx/Cu41Ni59/Nb/Cu41Ni59 ultrathin heterostructure was prepared by magnetron sputtering on a commercial silicon substrate covered by a silicon buffer layer prior the heterostructure deposition. The Co/CoOx composite layer provided strong exchange biasing (~ 1800 Oe) of the adjacent hard ferromagnetic Cu41Ni59 alloy layer, while the outer soft Cu41Ni59 alloy layer could be remagnetized by a weak external magnetic field creating controllable alignments with respect to the hard interior Cu41Ni59 alloy layer and the metallic Co layer as well. The thickness of the Cu41Ni59 alloy layers was varied between 0 and 25 nm, the Nb layer thickness was about 12 nm. Upon cycling the in-plane magnetic field in the range ± 6 kOe and the temperature close to the superconducting transition a memory effect has been observed [4]. If the magnetic field was dropped to zero from the initial field-cooling direction at 10 kOe, the system resistance dropped down to the almost superconducting low-resistive state. Changing polarity of the field, raising its magnitude to -6 kOe and dropping the field to zero again brought the system to the resistance at the normal conducting state. The bistability was repeatedly reproduced upon further cycling along the full magnetic hysteresis loop of the heterostructure. The both low- and high-resistive states at zero magnetic field were determined solely by pre-history of the field cycling and did not need biasing field to keep them steady. We refer the observed memory effect to generation of the triplet pairing at non-collinear magnetic configurations in the studied system. The support by DFG, and RFBR, grants Nos. 14-02-90018 (M.Yu.K) and 14-02-00793-a (L.R.T.), is gratefully acknowledged. 1. F.S. Bergeret, A. F. Volkov, and K.B. Efetov, Rev. Mod. Phys., 77 (2005) 1321. 2. Ya.V. Fominov, et al., JETP Lett., 77 (2003) 510. 3. Ya.V. Fominov, et al., JETP Lett., 91 (2010) 308. 4. V.I. Zdravkov, et al. Appl. Phys. Lett., 114 (2013) 0339903.
- Добавил в систему: Куприянов Михаил Юрьевич