Current–Voltage Characteristics of Commercial Ferroelectric Capacitors: Deviations from the Preisach Model

The hysteresis properties of ferroelectric PZT capacitors were investigated by measuring their cyclic current–voltage characteristics using a source-measure unit of a semiconductor device analyzer. The first-order reversal curve diagrams were obtained, which have a typical appearance for ferroelectric materials. Based on the obtained diagrams, the degree of correlation between the positive and negative coercive fields of ferroelectric domains was identified, and the deviations in their behavior from the Preisach model domains were determined. A peak-splitting phenomenon was observed, and some of its features were found.     

Analysis of the Electrohydrodynamic Flow in a Symmetric System of Electrodes by the Method of Dynamic Current–Voltage Characteristics

We have solved the problem of injection-type through electrohydrodynamic (EHD) flow in a closed channel. We have considered a model of a liquid with four types of ions. It is shown that a through EHD flow without internal vortices in the electrode gap is formed for the ratio 2 : 1 of the initial injection current from the electrodes in the channel. The structure of the flow in different parts of the channel and the integral characteristics of the flow have been analyzed. It is shown that for a quadratic function of injection at the electrodes, the current–voltage characteristic of the flow is also quadratic.     

Temperature Dependence of the Voltage Induced by Spin Current in a Manganite–Iridate Heterostructure

Physics of the Solid State - The temperature dependence of the voltage induced by spin current is studied in the epitaxial thin-film La0.7Sr0.3MnO3/SrIrO3 heterostructure deposited on a...     

The Effect of Contact Potential Difference on Current–Voltage Characteristics in Scanning Tunneling Spectroscopy

Technical Physics - Using the energy diagrams of asymmetric potential barriers, which are formed during the contact of two metals with different work functions, the effect of the contact potential...     

Temperature-Dependent Current–Voltage (I–V) and Capacitance–Voltage (C–V) Characteristics of Ni/Cu/n-InP Schottky Barrier Diodes

The current-voltage (I–V) and capacitance-voltage (C–V) characteristics of Ni/Cu/n-InP Schottky barrier diodes are studied over a wide temperature range, from 210 K to 420 K. The I–V characteristics display anomalous thermal behavior. The apparent barrier height decays, and the ideality factor grows at low temperatures, and the series resistances resulting from Cheung’s and Norde’s procedures are markedly temperature dependent. The nonlinearity of the Richardson plot and the strong temperature dependence of the Schottky-barrier parameters indicate that the interface is spatially inhomogeneous. Plots of the zero-bias barrier height as a function of 1/(2kT) points to a Gaussian distribution of barrier heights with 0.90 eV mean height and 0.014 eV standard deviation. When this distribution is accounted for, a Richardson of 6.5 A/(cm K)² results, relatively close to the 9.4/(cm K)² predicted by theory. We conclude that, combined with a Gaussian distribution of barrier heights, the thermionic-emission mechanism explains the temperature-dependent I–V and C–V characteristics of the studied Schottky-barrier diodes.     

A Chain of Fast Vortices and the Current–Voltage Characteristic of an Annular Josephson Junction

It is demonstrated that a chain of fast vortices produces a peak in the current–voltage characteristic of an annular Josephson junction coupled to a waveguide.     

Features of the Frequency Dependence of Capacitance–Voltage Characteristics of a Semiconductor Structure of a Photoelectric Converter Based on a p–n Junction with an Antireflective Film of Porous Silicon

Technical Physics - The frequency dependence of capacitance–voltage characteristics of a semiconductor structure with an antireflective film of porous silicon, which was formed by...     

Numerical Molecular Dynamics Simulation of the Fracture of a Ti–Al Intermetallic Nanocrystal

Doklady Physics - The results of numerical molecular dynamics simulation of the synthesis and fracture of a Ti–Al intermetallic nanocrystal under uniaxial tension are reported. It is shown...     

Enhancement of Critical Current Density in Graphite Doped MgB2 Wires

Graphite doped MgB2-xCx (x = 0.00, 0.05, 0.10) wires were fabricated via the in situ powder-in-tube method in flowing argon by using low carbon steel tubes as the sheath materials. With the increase of graphite concentration,the amount of unreacted graphite in the core area increases, and the average grain size of MgB2 decreases. It is found that the critical current density Jc can be significantly improved by graphite doping. The MgB2 wire with x = 0.05 exhibits the best Jc value of 16710 A/cm^2 at 6K, 4.5T, but the MgB1.9C0.1 wire has the highest Jc value of 2060 A/cm^2 at 6 K, 8 T. It is suggested that the enhancement of Jc is due to not only the improvement of the microstructure features but also the introduction of pinning centres.     

Schotky Barrier Height and Calculation of Voltage–Current Characteristics of Al/n-(SiC)1–x(AlN)x Diodes And 4H–SiC Heterojunctions

Russian Physics Journal - The Schottky barrier heights in the М/n-(SiC)1–x(AlN)x systems are obtained on the assumption of a high density of surface states in the region of the metal...     

Current–phase relations of a ring-trapped Bose–Einstein condensate with a weak link

The current–phase relations of a ring-trapped Bose–Einstein condensate interrupted by a rotating rectangular barrier are extensively investigated with an analytical solution. A current–phase diagram, single and multi-valued relation, is presented with a rescaled barrier height and width. Our results show that the finite size makes the current–phase relation deviate a little bit from the cosine form for the soliton solution in the limit of a vanishing barrier, and the periodic boundary condition selects only the plane wave solution in the case of high barrier. The reason for multi-valued current–phase relation is given by investigating the behavior of soliton solution.     

Effect of Dopant Concentration in a Base Layer on Photocurrent——Voltage Characteristics of Photovoltaic Power Converters

It is known that the p–n junction of an absorption region is a crucial part for power conversion efficiency of photovoltaic power converters. We fabricate four samples with different dopant concentrations in base layers.The dependences of power conversion efficiency and fill factor on input power are displayed by photocurrent–voltage measurement. Photoluminescence characteristics under open circuit and connected circuit conditions are also studied. It is found that the status of p–n junction mat...     

Binding Energies of Excitons in Square Quantum-Well Wires in the Presence of a Magnetic Field

The binding energies of the ground state of excitons in the GaAs/Ga1-xAlxAs square quantum-well wire in the presence of a magnetic field are investigated by using the variational method. It is assumed that the magnetic field is applied parallel to the axis of the wire. The calculations of the binding energy as a fimction of the wire size have been performed for infinite and finite confinement potentials. The contribution of the magnetic field makes the binding energy larger obviously, particularly for the wide wire, and the magnetic field is much more pronounced for the binding energy in a square quantum wire than that in a cylindrical quantum wire. The mismatch of effective masses between the well and the barrier is also considered in the calculation.     

Molecular dynamics simulations of the melting of Al–Ni nanowires

Molecular dynamics (MD) simulations were performed to investigate the influence of nickel (Ni) composition and nanowire thickness on the thermal properties of Al-x%Ni (at%) nanowires using the embedded atom model (EAM) potential. The melting of the nanowire was characterised by studying the temperature dependence of the cohesive energy and mean square displacement. The effect of the nanowire thickness on the cohesive energy, melting temperature, heat capacity as well as latent heat was studied in canonical ensemble. Moreover, the crystal stability of Al, Al-20%Ni, Al-40%Ni, Al-60%Ni, Al-80%Ni, Al₃Ni, Ni₃Al and Ni nanowires was studied at different temperatures using mean square displacement and cohesive energy.     

Current–time characteristic of the transient regime of electrohydrodynamic flow formation

The paper presents the results of computer simulation of the current–time characteristic (CTC) of a cell with low-conducting liquid. The basis of simulation is the complete set of electrohydrodynamic (EHD) equations. The injection and dissociation mechanisms of charge formation as well as field-enhanced dissociation are considered. The simulation is carried out in the needle–plane electrode system. The relation between sections of CTC and stages of EHD flow formation is revealed. The shape of CTC is shown to be dependent on mechanisms of charge formation, the ratio of the initial and steady-state ion concentrations and the mechanisms of charge transport.     

Luminescence Characteristics of a Low-Temperature Plasma Based on a Helium–Glutamine Mixture

Optics and Spectroscopy - The luminescence spectra of a low-temperature plasma of a pulse-periodic discharge in a He–Glu mixture at low pressures not exceeding several tens of Torr have been...     

Characteristics of the impact explosion initiation of HMX–energetic additive mixtures

Experimental data on the dependence of the conditions of explosion initiation in HMX-energetic additive mixtures by mechanical impact on the caloricity and content of the additive are presented. Introduction of various additives, such as boron, carborane, and some others, into HMX is shown to cause an increase in the sensitivity of the mixture. The increase in the sensitivity was explained by an additional heat release due to the chemical interaction between the oxygen-containing products of HMX decomposition and the energetic additive at impact-induced hotspots.     

Simulation of the Propagation Property of Metal Wires Terahertz Waveguides

The propagation property of metal wires terahertz waveguides is studied and simulated under the framework of the Sommerfeld model. The group velocity dispersion, attenuation amplitude, transverse magnetic mode and propagating energy have been obtained by numerically solving the complex eigenvalue equation for the propagation constant. It is found that the group velocity dispersion and attenuation amplitude decrease with the increasing radii of metal wires. The energy power within the dielectric layer increase with the increase of radiation frequency.