Ultra-fast vortex motion in dirty Nb-C superconductor with a close-to-perfect edge barrier

The ultra-fast dynamics of superconducting vortices harbors rich physics generic to nonequilibrium collective systems. The phenomenon of flux-flow instability (FFI), however, prevents its exploration and sets practical limits for the use of vortices in various applications. To suppress the FFI, a superconductor should exhibit a rarely achieved combination of properties: weak volume pinning, close-to-depairing critical current, and fast heat removal from heated electrons. Here, we demonstrate experimentally ultra-fast vortex motion at velocities of 10-15 km/s in a directly written Nb-C superconductor in which a close-to-perfect edge barrier orders the vortex motion at large current values. The spatial evolution of the FFI is described using the edge-controlled FFI model, implying a chain of FFI nucleation points along the sample edge and their development into self-organized Josephson-like junctions (vortex rivers). In addition, our results offer insights into the applicability of widely used FFI models and suggest Nb-C to be a good candidate material for fast single-photon detectors.Comment: 12 pages, 7 page

Cherenkov radiation of spin waves by ultra-fast moving magnetic flux quanta

Despite theoretical predictions for a Cherenkov-type radiation of spin waves (magnons) by various propagating magnetic perturbations, fast-enough moving magnetic field stimuli have not been available so far. Here, we experimentally realize the Cherenkov radiation of spin waves in a Co-Fe magnonic conduit by fast-moving (>1 km/s) magnetic flux quanta (Abrikosov vortices) in an adjacent Nb-C superconducting strip. The radiation is evidenced by the microwave detection of spin waves propagating a distance of 2 micrometers from the superconductor and it is accompanied by a magnon Shapiro step in its current-voltage curve. The spin-wave excitation is unidirectional and monochromatic, with sub-40 nm wavelengths determined by the period of the vortex lattice. The phase-locking of the vortex lattice with the excited spin wave limits the vortex velocity and reduces the dissipation in the superconductor.Comment: 11 pages, 5 page

SOLUBILITY OF NEODYMIUM IN GALLIUM-INDIUM ALLOYS

Reprocessing of short cooled SNFrequires developmentof non-aqueous methods.For solving the issue«molten salt-liquid metal» systemsare considered as promising media. Ga-In alloys containing 90.0, 70.0 and 50.0 wt.% of gallium were chosen as objects of research. Solubility of Nd in the alloys was measured between 425-1073 K. It was found that in the Ga-In alloysNdinteracts with gallium. Indium acts as an indifferent additive and changes melting point and physical propertiesof alloys

Silicic p–i–n-photodiode with small dark current

The influence of circular metallization of the reverse side of p–i–n-photodiode crystal based on highly ohm silicon on it’s characteristics are explored. The dark current can be decreased by an order, at the same time losses of current monochromatic sensitiveness on a wave-length 1,06 mkm do not exceed 15%. The characteristics of the offered photodiode show that it can be recommended as base construction at serial product designing

Kinetic features of mediator bioelectrocatalytic oxidation of glucose by "crude" bacterial extracts

«Сырой» белковый экстракт микробных клеток изучали как биоэлектрокатализатор в реакции окисления глюкозы. Такой экстракт, полученный из культуры Escherichia coli BB, рассматривался в данной работе как модельная система, содержащая все ферменты жизненного цикла бактерий

The 2021 Magnonics Roadmap

Magnonics is a budding research field in nanomagnetism and nanoscience that addresses the use of spin waves (magnons) to transmit, store, and process information. The rapid advancements of this field during last one decade in terms of upsurge in research papers, review articles, citations, proposals of devices as well as introduction of new sub-topics prompted us to present the first roadmap on magnonics. This is a collection of 22 sections written by leading experts in this field who review and discuss the current status besides presenting their vision of future perspectives. Today, the principal challenges in applied magnonics are the excitation of sub-100 nm wavelength magnons, their manipulation on the nanoscale and the creation of sub-micrometre devices using low-Gilbert damping magnetic materials and its interconnections to standard electronics. To this end, magnonics offers lower energy consumption, easier integrability and compatibility with CMOS structure, reprogrammability, shorter wavelength, smaller device features, anisotropic properties, negative group velocity, non-reciprocity and efficient tunability by various external stimuli to name a few. Hence, despite being a young research field, magnonics has come a long way since its early inception. This roadmap asserts a milestone for future emerging research directions in magnonics, and hopefully, it will inspire a series of exciting new articles on the same topic in the coming years