Scaling Behavior of Quasi-One-Dimensional Vortex Avalanches in Superconducting Films

Scaling behaviour of dynamically driven vortex avalanches in superconducting YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ films deposited on tilted crystalline substrates has been observed using quantitative magneto-optical imaging. Two films with different tilt angles are characterized by the probability distributions of avalanche size in terms of the number of moving vortices. It is found in both samples that these distributions follow power-laws over up to three decades, and have exponents ranging between 1.0 and 1.4. The distributions also show clear finite-size scaling, when the system size is defined by the depth of the flux penetration front -- a signature of self-organized criticality. A scaling relation between the avalanche size exponent and the fractal dimension, previously derived theoretically from conservation of the number of magnetic vortices in the stationary state and shown in numerical simulations, is here shown to be satisfied also experimentally.Comment: 7 pages, 5 figure

Quasi-one-dimensional intermittent flux behavior in superconducting films

Intermittent filamentary dynamics of the vortex matter in superconductors is found in films of YBa2Cu3O7-δ deposited on tilted substrates. Deposition of this material on such substrates creates parallel channels of easy flux penetration when a magnetic field is applied perpendicular to the film. As the applied field is gradually increased, magneto-optical imaging reveals that flux penetrates via numerous quasi-one-dimensional jumps. The distribution of flux avalanche sizes follows a power law, and data collapse is obtained by finite-size scaling, with the depth of the flux front used as crossover length. The intermittent behavior shows no threshold value in the applied field, in contrast to conventional flux jumping. The results strongly suggest that the quasi-one-dimensional flux jumps are of a different nature than the thermomagnetic dendritic (branching) avalanches that are commonly found in superconducting films

Graphoepitaxial growth of CeO2 thin films on tilted-axes NdGaO3 substrates by pulsed laser deposition

CeO2 thin films were grown on NdGaO3 tilted-axes substrates by pulsed laser deposition (PLD) showing three-dimensional graphoepitaxial (3DGE) growth in the whole studied range of substrate tilt angles γ = 5-27º. Deviations from the tangent dependence can be divided into a systematic negative part and local deviations near certain film tilt angles. The systematic deviation may be explained as the effect of completely-strained coherent growth of the bottom layers of CeO2 film. Minimization of the surface energy near the small-index crystallographic planes (012) and (013) may account for the local deviations from the calculated dependence. The width of the rocking curve and the lattice constant variation for the 3DGE CeO2 films increase almost linearly with the substrate tilt angle until 19º and decrease for higher γ. At different deposition rates the 3DGE CeO2 film exhibits three possible structures: (i) relaxed completely oxygenated films at very low deposition rate, (ii) completely strained well-oxygenated films at moderate deposition rates, and (iii) oxygen-deficient films consisting of two layers at high deposition rates. The deviations of orientation of the film from the 3DGE formula are set by the lattice constant c in the direction normal to the (110) SICP of the substrate, which, in turn, depends on oxygen deficiency and the level of strain, introduced into the film by lattice mismatch with the substrate.publishe

Review of laser scanning methods for microelectronic semiconductor structures investigation

The development and widespread of high-tech microelectronic products impose increased requirements on the quality and reliability of microcircuits. The most effective methods for reliability improvement of electronic systems include diagnostic non-destructive testing (NDT) methods and selective destructive testing in special cases. Studies using visual inspection and electrical testing, consisting of functional and parametric testing, do not provide enough information to detect latent defects (for example, macro-defects in SiO 2 layers in CMOS chips) and to detect fakes and counterfeits. A fake integrated circuit (IC) may contain an undeclared malicious modification of the circuit, called hardware bugs. The common ICs studying tools are systems based on microfocus X-ray sources, scanning acoustic microscopes, optical and scanning electron microscopes, and X-ray fluorescence spectroscopes. Products destruction avoidance is a fundamental point, for example, for the technological process control in crystal manufacturing. Investigation of ICs using a light microscope is one of the most accessible and widespread method of microchip NDT. Semiconductor ICs structure scanning from the side of the device layer is limited by the shielding effect of metallization, since the metal is opaque for light. This limitation can be overcome by an alternative approach to microchip scanning based on irradiating the IC from the side of the substrate with laser sources in the near-IR range. This paper provides a brief overview of the major methods used in laser scanning microscopy to analyze the structures, responses, and features of the operating modes of semiconductor circuits. The main advantages and limitations in the use of optical methods are described, as well as what information about the product can be obtained as a result of laser scanning

Nonlinear acousto-electric transport in a two-dimensional electron system

We study both theoretically and experimentally the nonlinear interaction between an intense surface acoustic wave and a two-dimensional electron plasma in semiconductor-piezocrystal hybrid structures. The experiments on hybrid systems exhibit strongly nonlinear acousto-electric effects. The plasma turns into moving electron stripes, the acousto-electric current reaches its maximum, and the sound absorption strongly decreases. To describe the nonlinear phenomena, we develop a coupled-amplitude method for a two-dimensional system in the strongly nonlinear regime of interaction. At low electron densities the absorption coefficient decreases with increasing sound intensity, whereas at high electron density the absorption coefficient is not a monotonous function of the sound intensity. High-harmonic generation coefficients as a function of the sound intensity have a nontrivial behavior. Theory and experiment are found to be in a good agreement.Comment: 27 pages, 6 figure

Application of machine vision technology for focused laser effect accuracy improvement in microelectronic structures research and semiconductor microprocessing

Machine vision is a field of artificial intelligence that deals with processing images and videos using special algorithms. This allows devices to analyze visual information. Machine vision helps with tasks such as pattern recognition, image segmentation, object detection, and tracking. In microscopy, machine vision plays an important role, particularly in laser scanning microscopy (LSM). Laser scanning microscopy, laser scribing, and laser correction of the topology of semiconductor crystals are important technological processes in the production, control and adjustment of semiconductor crystals both on debug samples and as part of a test batch on a wafer. Laser exposure allows not only mechanically separate crystals, but also carry out more delicate and minimally invasive actions, in particular, adjustments to the values of thin-film resistors or burning of bridges necessary to adjust the circuit and disable unused blocks of the crystal. The paper lists the main parameters of the positioning system as part of the laser scanning setup, their impact on the quality of scanning and exposure to focused radiation at control points. The principles of machine vision algorithms when working with the image of the scanned object and the results of testing in the task of automated laser burning of bridges on a semiconductor wafer are described. Since the number of bridges can reach tens of thousands, and positioning systems have significant errors, machine vision allows you to correct the area and accuracy of laser exposure at any stage of scanning, which significantly improves the quality and efficiency of the process

Hydrostatic and osmotic pressure study of the RNA hydration

The tertiary structure of nucleic acids results from an equilibrium between electrostatic interactions of phosphates, stacking interactions of bases, hydrogen bonds between polar atoms and water molecules. Water interactions with ribonucleic acid play a key role in its structure formation, stabilization and dynamics. We used high hydrostatic pressure and osmotic pressure to analyze changes in RNA hydration. We analyzed the lead catalyzed hydrolysis of tRNAPhe from S. cerevisiae as well as hydrolytic activity of leadzyme. Pb(II) induced hydrolysis of the single phosphodiester bond in tRNAPhe is accompanied by release of 98 water molecules, while other molecule, leadzyme releases 86

МАЗЬ ОФЛОМЕЛИД. КЛИНИКО-ЛАБОРАТОРНАЯ ЭФФЕКТИВНОСТЬ И ПЕРЕНОСИМОСТЬ У БОЛЬНЫХ С ИНФЕКЦИОННЫМИ ПРОЦЕССАМИ КОЖИ И МЯГКИХ ТКАНЕЙ

The paper presents the results of a multicenter postmarketing study of Oflomelid ointment versus levosin and levomecol ointments in 301 patients with different purulent diseases of the skin, soft tissues, and bones, diabetic foot syndrome, trophic ulcers of different etiologies, postoperative purulent wounds, chronic posttraumatic osteomyelitis, burns and frostbites, acute and chronic purulent diseases of the skin and soft tissues. Oflomelid ointment shows a high clinical and bacteriological efficacy in stages I and II wound process along with good analgesic activity for the topical treatment of purulent processes of different etiologies and sites. Objectivization of the findings is based on the results of qualitative and quantitative microbiological analyses, wound imprint cytology, and trends in the systemic and local clinical picture.В статье представлены результаты многоцентрового постмаркетингового сравнительного исследования мази Офломелид по сравнению с мазями левосин и левомеколь у 301 пациента с различными гнойными заболеваниями кожи, мягких тканей и костей, синдромом диабетической стопы, трофическими язвами различной этиологии, послеоперационными гнойными ранами, хроническим посттравматическим остеомиелитом, ожогами и отморожениями, острыми и хроническими гнойными заболеваниями кожи и мягких тканей. Показана высокая клиническая и бактериологическая эффективность мази Офломелид при I и II стадиях течения раневого процесса наряду с хорошим анальгезирующим действием для местного лечения гнойных процессов различной этиологии и локализации. Объективизация полученных данных основана на результатах качественных и количественных микро-биологических исследований, цитологии раневых отпечатков, динамики общей и местной клинической картины