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Cooper pair splitting in diffusive magnetic SQUIDs
Physical Review B: Condensed Matter and Materials Physics. 2017. Vol. 95. No. 9. P. 094508-1-094508-6.
We study Josephson junctions with weak links consisting of two parallel disordered arms with magnetic
properties: ferromagnetic, half-metallic, or normal with magnetic impurities. In the case of long links, the
Josephson effect is dominated by mesoscopic fluctuations. In this regime, the system realizes a phi_0 junction with
sample-specific phi_0 and critical current. Cooper pair splitting between the two arms plays a major role and leads
to 2*Phi_0 periodicity of the current as a function of flux between the arms. We calculate the current and its flux and
polarization dependence for the three types of magnetic links.
Keywords: mesoscopic superconductivityмезоскопическая сверхпроводимостьsuperconducting hybrid structuresSQUIDСКВИДсверхпроводящие гибридные структуры
Publication based on the results of:
Stroganov P. L., Ya. V. Fominov, / Cornell University. Series cond-mat "arxiv.org". 2017. No. arXiv:1708.05089.
We consider ballistic SQUIDs with spin filtering inside half-metallic ferromagnetic arms. A singlet Cooper pair cannot pass through an arm in this case, so the Josephson current is entirely due to the Cooper pair splitting, with two electrons going to different interferometer arms. In order to elucidate the mechanisms of Josephson transport due to split ...
Added: October 18, 2017
Stroganov P. L., Ya.V. Fominov, Physical Review B: Condensed Matter and Materials Physics 2017 Vol. 96 No. 17 P. 174508-1-174508-13
We consider ballistic SQUIDs with spin filtering inside half-metallic ferromagnetic arms. A singlet Cooper pair
cannot pass through an arm in this case, so the Josephson current is entirely due to the Cooper pair splitting, with
two electrons going to different interferometer arms. In order to elucidate the mechanisms of Josephson transport
due to split Cooper pairs, we ...
Added: November 17, 2017
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We theoretically investigate asymmetric two-junction SQUIDs with different current-phase relations in the two Josephson junctions, involving higher Josephson harmonics. Our main focus is on the "minimal model" with one junction in the SQUID loop possessing the sinusoidal current-phase relation and the other one featuring additional second harmonic. The current-voltage characteristic (CVC) turns out to be ...
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An analytical approach that makes it possible to reconstruct the current–phase relation (CPR) in Josephson
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Arutyunov K., Lehtinen J. S., Beilstein Journal of Nanotechnology 2020 Vol. 11 P. 417-420
Chain of superconductor-insulator-superconductor junctions based on Al-AlOx-Al... lift-off fabricated nanostructures was measured at ultra-low temperatures. At zero magnetic field the low current bias dynamic resistance can reach values ~1011 W. The system has been proved to provide a decent quality current biasing circuit enabling observation of Coulomb blockade and Bloch oscillations in ultra-narrow Ti nanowires ...
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The interplay of Anderson localization and electron-electron interactions is known to lead to enhancement of superconductivity due to multifractality of electron wave functions. We develop the theory of multifractally-enhanced superconducting states in two-dimensional systems in the presence of spin-orbit coupling. Using the Finkel'stein nonlinear sigma model, we derive the modified Usadel and gap equations that ...
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Arutyunov K., M. : Lebedev Institute, 2017
Superconducting properties of metallic nanowires can be entirely different from those of bulk superconductors because of the dominating role played by thermal and quantum fluctuations of the order parameter. For superconducting channels with diameters below ∼ 50 nm fluctuations of the phase of the complex order parameter - the phase slippage - lead to non-zero ...
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A nonmonotonic dependence of the critical Josephson supercurrent on the injection current
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Камашев А. А., Гарифьянов Н. Н., Валидов А. А. et al., Физика твердого тела 2022 Т. 64 № 9 С. 1201-1210
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Arutyunov K., Lehtinen J. S., Radkevich A. A. et al., Journal of Magnetism and Magnetic Materials 2018 Vol. 459 P. 356-358
Quasi-one-dimensional superconducting channels host sound-like plasma modes propagating along the
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Рассматривается длинный диффузный контакт Джозефсона, слабой связью в котором является тонкий бислой нормальный металл (N)–ферромагнетик (F), так что N и F образуют параллельные связи между сверхпроводниками S. Показано, что сверхпроводимость в такой слабой связи описывается эффективным одномерным уравнением Узаделя, содержащим ослабленное обменное поле, а также распаривающий член. Механизм распаривания основан на неотъемлемой неоднородности бислоя и ...
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Temu E., Lahteenmaki P., Golubev D. et al., Journal of Low Temperature Physics 2017 Vol. 189 P. 204-216
We have employed noise thermometry for investigations of thermal relaxation
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M. : Faculty of Physics, MSU, 2017
The Low Temperature Physics Conference is an international event held every three years, under the auspices of the IUPAP through its Commission C5 on Low Temperature Physics. The aim of these conferences is to exchange information and views among the members of the international scientific community in the general field of Low Temperature Physics. It ...
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We theoretically predict that the critical current Ic and magnetization M of a hybrid superconductor/normal-metal (SN) strip may have nonmonotonous dependence on a perpendicular magnetic field—so-called peak effect. In contrast to familiar peak effect, which is connected either with vortex entry to the superconductor or with peculiarities of vortex pinning, the found phenomenon exists at ...
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This article represents a mini review of our obtained results about of superconducting spin-valve effect in heterostructures with ferromagnetic Heusler alloy layers.
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