Oscillatory superconducting transition temperature in superconductor/antiferromagnet heterostructures

One of the most famous proximity effects at ferromagnet/superconductor (F/S) interfaces is partial conversion of singlet superconductivity to triplet pairing correlations. Due to the presence of macroscopic exchange field in the ferromagnet the Cooper pairs penetrating into the ferromagnet from the superconductor acquire a finite momentum there. The finite-momentum pairing manifests itself, in particular, as a nonmonotonic dependence of the critical temperature of the bilayer on the thickness of the F layer. Here we predict that despite the absence of the macroscopic exchange field the critical temperature of the antiferromagnet/superconductor (AF/S) bilayers also exhibit nonmonotonic (oscillating) dependence on the AF layer thickness. It is a manifestation of the proximity-induced Neel-type triplet correlations, which acquire finite total pair momentum and oscillate in the AF layer due to the Umklapp electron scattering processes at the AF/S interface. Our prediction can provide a possible explanation for a number of recently published experimental observations of the critical temperature of AF/S bilayers

PSYCHOLOGICAL WELL-BEING AND CYBER-COMMUNICATIVE ADDICTION OF STUDENTS

This study examines one of the factors of cyber-communicative dependence of students, namely, the level of psychological well-being. It has been proven that students with a low level of psychological well-being are most susceptible to the emergence and development of cyber-communication addiction.В данном исследовании рассматривается один из факторов киберкоммуникативной зависимости студенческой молодежи, а именно уровень психологического благополучия. Доказано, что в наибольшей степени подвержены возникновению и развитию киберкоммуникативной зависимости студенты с низким уровнем психологического благополучия

Разработка многофункционального портала кафедры

This paper describes the results of the development and implementation of several software component on the portal of the department.В работе описаны результаты разработки и внедрения некоторых интерактивных компонент на портал кафедры

Зачем кафедре сайт?

And what to do to portal department was the first information unit, demanded by all stakeholders of the educational process.Что и как нужно сделать, чтобы кафедральный портал был первой информационной единицей, востребованной всеми заинтересованными участниками учебного процесса

Efficiency of electron cooling in cold-electron bolometers with traps

Electron on-chip cooling from the base temperature of 300 mK is very important for highly sensitive detectors operating in space due to problems of dilution fridges at low gravity. Electron cooling is also important for ground-based telescopes equipped with 3He cryostats being able to function at any operating angle. This work is aimed at the investigation of electron cooling in the low -temperature range. New samples of cold-electron bolometers with traps and hybrid superconducting/ferromagnetic absorbers have shown a temperature reduction of the electrons in the refrigerator junctions from 300 to 82 mK, from 200 to 33 mK, and from 100 to 25 mK in the idle regime without optical power load. The electron temperature was determined by solving heat balance equa-tions with account of the leakage current, sixth power of temperature in the whole temperature range, and the Andreev current using numerical methods and an automatic fit algorithm

Response of a cold-electron bolometer on thz radiation from a long yba2cu3o7−δ bicrystal josephson junction

The response of the Cold-Electron Bolometers (CEBs), integrated into a 2-D array of dipole antennas, has been measured by irradiation from YBa2Cu3O7−δ (YBCO) 50 \ub5m long Josephson junction into the THz region at frequencies from 0.1 to 0.8 THz. The possibility of controlling the amplitude-frequency characteristic is demonstrated by the external magnetic field in the traveling wave regime of a long Josephson junction. The YBCO junction has been formed on the bicrystal Zr1−xYxO2 (YSZ) substrate by magnetron sputtering and etching of the film. CEBs have been fabricated using an Al multilayer structure by a self-aligned shadow evaporation technique on Si substrate. Both receiver and oscillator have been located inside the same cryostat at 0.3 K and 2.7 K plates, respectively

Microwave photon detection by an Al Josephson junction

An aluminium Josephson junction (JJ), with a critical current suppressed by a factor of three compared with the maximal value calculated from the gap, is experimentally investigated for application as a threshold detector for microwave photons. We present the preliminary results of measurements of the lifetime of the superconducting state and the probability of switching by a 9 GHz external signal. We found an anomalously large lifetime, not described by the Kramers\u27 theory for the escape time over a barrier under the influence of fluctuations. We explain it by the phase diffusion regime, which is evident from the temperature dependence of the switching current histograms. Therefore, phase diffusion allows for a significant improvement of the noise immunity of a device, radically decreasing the dark count rate, but it will also decrease the single-photon sensitivity of the considered threshold detector. Quantization of the switching probability tilt as a function of the signal attenuation for various bias currents through the JJ is observed, which resembles the differentiation between N and N + 1 photon absorption

Complete TcT_c suppression and N\'eel triplets-mediated exchange in antiferromagnet-superconductor-antiferromagnet trilayers

An antiferromagnetic insulator (AFI) bearing a compensated interface to an adjacent conventional superconductor (S) has recently been predicted to generate N\'eel triplet Cooper pairs, whose amplitude alternates sign in space. Here, we theoretically demonstrate that such N\'eel triplets enable control of the superconducting critical temperature in an S layer via the angle between the N\'eel vectors of two enclosing AFI layers. This angle dependence changes sign with the number of S monolayers providing a distinct signature of the N\'eel triplets. Furthermore, we show that the latter mediate a similarly distinct exchange interaction between the two AFIs' N\'eel vectors.Comment: 7 pages, 4 figure