Mesoscopic field and current compensator based on a hybrid superconductor-ferromagnet structure

A rather general enhancement of superconductivity is demonstrated in a hybrid structure consisting of submicron superconducting (SC) sample combined with an in-plane ferromagnet (FM). The superconducting state resists much higher applied magnetic fields for both perpendicular polarities, as applied field is screened by the FM. In addition, FM induces (in the perpendicular direction to its moment) two opposite current-flows in the SC plane, under and aside the magnet, respectively. Due to the compensation effects, superconductivity persists up to higher applied currents. With increasing current, the sample undergoes SC-"resistive"-normal state transitions through a mixture of vortex-antivortex and phase-slip phenomena.Comment: 4 pages, 5 figures, to appear in Phys. Rev. Let

Vertical pairing of identical particles suspended in the plasma sheath

It is shown experimentally that vertical pairing of two identical microspheres suspended in the sheath of a radio-frequency (rf) discharge at low gas pressures (a few Pa), appears at a well defined instability threshold of the rf power. The transition is reversible, but with significant hysteresis on the second stage. A simple model, which uses measured microsphere resonance frequencies and takes into account besides Coulomb interaction between negatively charged microspheres also their interaction with positive ion wake charges, seems to explain the instability threshold quite well.Comment: 4 pages, 6 figures. to appear in Phys. Rev. Lett. 86, May 14th (2001

Nonlinear dynamics of large amplitude dust acoustic shocks and solitary pulses in dusty plasmas

We present a fully nonlinear theory for dust acoustic (DA) shocks and DA solitary pulses in a strongly coupled dusty plasma, which have been recently observed experimentally by Heinrich et al. [Phys. Rev. Lett. 103, 115002 (2009)], Teng et al. [Phys. Rev. Lett. 103, 245005 (2009)], and Bandyopadhyay et al. [Phys. Rev. Lett. 101, 065006 (2008)]. For this purpose, we use a generalized hydrodynamic model for the strongly coupled dust grains, accounting for arbitrary large amplitude dust number density compressions and potential distributions associated with fully nonlinear nonstationary DA waves. Time-dependent numerical solutions of our nonlinear model compare favorably well with the recent experimental works (mentioned above) that have reported the formation of large amplitude non-stationary DA shocks and DA solitary pulses in low-temperature dusty plasma discharges.Comment: 9 pages, 4 figures. To be published in Physical Review

Freezing and melting of 3D complex plasma structures under microgravity conditions driven by neutral gas pressure manipulation

Freezing and melting of large three-dimensional complex plasmas under microgravity conditions is investigated. The neutral gas pressure is used as a control parameter to trigger the phase changes: Complex plasma freezes (melts) by decreasing (increasing) the pressure. Evolution of complex plasma structural properties upon pressure variation is studied. Theoretical estimates allow us to identify main factors responsible for the observed behavior.Comment: Phys. Rev. Lett. (in press); 4 pages, 4 figure

Fluid-solid phase transitions in 3D complex plasmas under microgravity conditions

Phase behavior of large three-dimensional complex plasma systems under microgravity conditions onboard the International Space Station is investigated. The neutral gas pressure is used as a control parameter to trigger phase changes. Detailed analysis of structural properties and evaluation of three different melting/freezing indicators reveal that complex plasmas can exhibit melting by increasing the gas pressure. Theoretical estimates of complex plasma parameters allow us to identify main factors responsible for the observed behavior. The location of phase states of the investigated systems on a relevant equilibrium phase diagram is estimated. Important differences between the melting process of 3D complex plasmas under microgravity conditions and that of flat 2D complex plasma crystals in ground based experiments are discussed.Comment: 13 pages, 10 figures; submitted to Phys. Rev.

Unified analytical algorithm for identification of component composition of winemaking products

The article discusses a unified analytical algorithm for identification of component composition of winemaking products, established in the new national standard GOST R 59570-2021 «Winemaking products. Identification of component in terms of determination of the origin of ethanol and other compounds of physical-chemical composition». The standard provides modern scientific data on winemaking products, as well as data on natural, agrotechnical and technological factors that can impact the component composition of products to interpret the results of analytical evaluations. The article provides practical examples of use of analytical methods established in the standard for the study of winemaking products produced in Russia, Kazakhstan, Armenia and foreign countries

Current-voltage characteristics of quasi-one-dimensional superconductors: An S-curve in the constant voltage regime

Applying a constant voltage to superconducting nanowires we find that its IV-characteristic exhibits an unusual S-behavior. This behavior is the direct consequence of the dynamics of the superconducting condensate and of the existence of two different critical currents: j_{c2} at which the pure superconducting state becomes unstable and j_{c1}<j_{c2} at which the phase slip state is realized in the system.Comment: 4 pages, 5 figures, replaced with minor change

Large Magnetoresistance Oscillations in Mesoscopic Superconductors Due to Current-Excited Moving Vortices

We show in the case of a superconducting Nb ladder that a mesoscopic superconductor typically exhibits magnetoresistance oscillations whose amplitude and temperature dependence are different from those stemming from the Little-Parks effect. We demonstrate that these large resistance oscillations (as well as the monotonic background on which they are superimposed) are due to {\it current-excited moving vortices}, where the applied current in competition with the oscillating Meissner currents imposes/removes the barriers for vortex motion in increasing magnetic field. Due to the ever present current in transport measurements, this effect should be considered in parallel with the Little-Parks effect in low-$T_c$ samples, as well as with recently proposed thermal activation of dissipative vortex-antivortex pairs in high-$T_c$ samples

Dynamics of lane formation in driven binary complex plasmas

The dynamical onset of lane formation is studied in experiments with binary complex plasmas under microgravity conditions. Small microparticles are driven and penetrate into a cloud of big particles, revealing a strong tendency towards lane formation. The observed time-resolved lane formation process is in good agreement with computer simulations of a binary Yukawa model with Langevin dynamics. The laning is quantified in terms of the anisotropic scaling index, leading to a universal order parameter for driven systems.Comment: 4 pages, 3 figures, movies available at http://www.mpe.mpg.de/pke/lane-formation