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Upper Critical Field of a Two-Band SrFe(2-x)Ni(x)As(2) Superconductor
JETP Letters. 2020. Vol. 111. No. 7. P. 403–407.
Мальцев Е. И., Власенко В. А., Соболевский О. А., Садаков А. В., Массалимов Б. И., Перваков К. С.
The upper critical field of an iron-based SrFe2 − xNixAs2 superconductor single crystal is measured for the first time in longitudinal and transverse magnetic fields up to 16 T in the basal ab plane and to it along the c axis. The Hc2(0) values are 18 and 25 T for H ∥ c and H ∥ ab, respectively. The anisotropy of the upper critical field γ(T) = Habc2 / Hcc2 decreases monotonically to 1.4 with decreasing temperature. The temperature dependence of Hc2 is not described fully by the Werthamer–Helfand–Hohenberg model taking into account the influence of orbital and spin paramagnetic effects. However, an effective two-band model reproduces well the measured temperature dependence. This indicates the two-band nature of this superconductor, where one of the bands is almost isotropic. According to the two-band model approximation, the contribution from the anisotropic band dominates near Tc, whereas the main contribution at low temperatures comes from the isotropic band with a lower diffusion coefficient.
Dikhtievskaya K., Argunov E., Карцев А. И. et al., The Journal of Physical Chemistry Letters 2026 Vol. 17 No. 17 P. 4999–5004
In this study we revealed the effect of scandium doping on the electronic and superconducting properties of the MgB2 compound. Calculations demonstrate that Sc substitutes for Mg atoms, acting as an electron donor. Mg substitution diminishes the density of states in the σ-band and attenuates the electron–phonon coupling, thereby elucidating the reduction in critical temperature. Simultaneously, ...
Added: June 2, 2026
S. A. Andreeva, Dzhikirba K. R., Shibalov M. V. et al., Physical Review B: Condensed Matter and Materials Physics 2026 Vol. 113 No. 10 Article L100503
In present work we report the first observations of two-dimensional plasma resonance with linear dispersion in superconducting NbN films fabricated by atomic layer deposition on sapphire and high-resistive (HR) silicon substrates. We have detected several consecutive resonance dips in THz transmission of the sample processed into the disc geometry. Increasing temperature results both in the ...
Added: March 12, 2026
Lukmanova R.M., Cohn I.A., Minakova V. E. et al., Physical Review B: Condensed Matter and Materials Physics 2025 Vol. 111 No. 22 Article 224510
The magnetoresistance of superconductor–topological insulator–superconductor structures, with indium as the superconductor and TaSe3 as the topological insulator, shows steplike features on the resistance under magnetic fields. These resistance steps result from the suppression of superconductivity, induced by the superconducting proximity effect in both the bulk and surface states of the topological insulator. The position and ...
Added: March 11, 2026
Vyacheslav D. Neverov, Karabassov T., Andrey V. Krasavin et al., Research 2026 Vol. 9 Article 1087
Majorana zero modes (MZMs) localized in vortex cores of topological superconductors are widely regarded promising building blocks for fault-tolerant quantum computation. However, their unambiguous detection is hindered by the extremely small energy spacing separating them from conventional Caroli-de Gennes-Matricon states. Using a microscopic Bogoliubov-de Gennes approach, we demonstrate that nonmagnetic impurities, rather than suppressing, can ...
Added: February 17, 2026
Kononova N., В кн.: XII Международная молодежная научная школа-конференция «Современные проблемы физики и технологий».: НИЯУ МИФИ, 2025. С. 167–169.
В работе исследованы термодинамические характеристики сверхпроводящего конденсата (вихревой материи), характерной для однозонных сверхпроводников в режиме перехода из первого рода во второй. На основе анализа изменения зависимости энергии Гиббса системы вихрей от внешнего магнитного поля сделаны выводы о характерных типах зависимости F(B) для такого перехода. Результаты демонстрируют, что для однозонных сверхпроводников в режиме межтиповой сверхпроводимости наблюдается ...
Added: February 2, 2026
Semenok D., Zhou D., Chen W. et al., Annalen der Physik 2025 Vol. 538 No. 1 Article e00467
We review five years of experimental and theoretical attempts (2020–2025) to enhance the superconducting critical temperature (Tc) of hydrogen-rich compounds by alloying binary superhydrides with additional elements. Despite predictions of higher Tc in ternary systems such as La–Y–H, La–Ce–H, and Ca–Mg–H, experiments consistently show that the maximum Tc in disordered ternary superhydrides does not exceed that of the ...
Added: January 24, 2026
Vyacheslav D. Neverov, Kalashnikov A., Andrey V. Krasavin et al., Beilstein Journal of Nanotechnology 2026 Vol. 17 P. 57–62
We present a comprehensive microscopic study of the intermediate mixed state in superconductors of the intertype (IT) regime separating types I and II. Using fully self-consistent Bogoliubov–de Gennes calculations for a lattice model, we analyze few-vortex configurations across the entire temperature range 0 < T < Tc. Our results demonstrate the key features of IT superconductivity, ...
Added: January 8, 2026
Tomayeva M., Vyacheslav D. Neverov, Andrey V. Krasavin et al., Beilstein Journal of Nanotechnology 2025 Vol. 16 P. 2265–2273
In the ballistic regime at finite temperatures, the proximity effect diminishes following an exponential pattern; however, at low or zero temperatures, this transition alters to a decay characterized by a power law with a dimensionality-dependent exponent. Here, we extend the current understanding of the proximity effect by exploring the role of normal metal–superconductor (NS) junction ...
Added: January 8, 2026
Ивашенцева И. В., Каурова Н. С., Воронов Б. М. et al., St. Petersburg Polytechnical University Journal: Physics and Mathematics 2025 Vol. 18 No. 3.2 P. 129–133
This paper focuses on the study of reactive magnetron sputtering thin NbN films for sensitization of hot electron bolometers. HEB will be utilized in the Millimetron space observatory. The main principle of operation is a superconductivity that is experimentally observed when NbN film is cooled to the temperature of a liquid helium. At a critical ...
Added: December 24, 2025
Третьяков И. В., Каурова Н. С., Ивашенцева И. В. et al., Журнал технической физики 2025 Т. 94 № 7 С. 1102–1110
The influence of the magnetron deposition process parameters for a thin 4–5 nm NbN superconducting niobium nitride film and the NbN HEB mixer fabrication technology on the spread of their key parameters was experimentally studied to minimize this spread. In addition to optimizing the NbN film deposition process, uniformity of the NbN HEB mixer parameters ...
Added: December 23, 2025
Khudchenko A., Turygin S., Golubev E. et al., Proceedings of SPIE 2025 Vol. 13102 P. 858–862
The Millimetron Space Observatory will be equipped with the cryogenically cooled instrument for a Space-Earth Very Large Baseline Interferometry (S-E VLBI). It will be a multi-channel heterodyne receiver with 7mm, 3mm, 1.3mm and 0.8mm channels. The VLBI instrument will have a multi-frequency capability, provided by signal splitting in the input optics and by back-end functionalities. ...
Added: December 23, 2025
Третьяков И. В., Худченко А. В., Рудаков К. И. et al., IEEE Transactions on Terahertz Science and Technology 2024 Vol. 15 No. 2 P. 191–199
The study of the origin and transport of water in the universe is an important part of the scientific program of the Millimetron space observatory. This will be made possible by observations conducted in single-dish mode using an onboard instrument—the high-resolution spectrometer (HRS). This instrument incorporates heterodyne array receivers operating within the range $0.5 -2.7$ ...
Added: December 23, 2025
Karabassov T., Bobkova I. V., Pavel M. Marychev et al., Beilstein Journal of Nanotechnology 2025 Vol. 17 P. 15–23
The diode effect in superconducting materials has been actively investigated in recent years. Plenty of different devices have been proposed as a platform to observe the superconducting diode effect. In this work, we discuss the possibility of a highly efficient superconducting diode design with controllable polarity. We propose a mesoscopic device that consists of two ...
Added: December 22, 2025