Gap Surface Waves in a System of Two Elastic Superconducting Semispaces Separated by a Narrow Gap

2011 ◽  
Vol 78 (6) ◽  
Author(s):  
K. Ghazaryan ◽  
R. Ghazaryan ◽  
O. Hachkevych ◽  
P. Marzocca
Keyword(s):  
Magnetic Field ◽  
Coupling Effect ◽  
Harmonic Wave ◽  
Constitutive Relations ◽  
Electrical Current ◽  
Narrow Gap ◽  
Plane Harmonic Wave ◽  
Relative Thickness ◽  
Elastic Substrates ◽  
Magnetoelastic Waves

This paper deals with the magnetoelastic interactions for a structure consisting of two elastic current carrying superconducting substrates, separated by a gap (vacuum). The two elastic substrates, which have no acoustic contacts, are coupled by a magnetic field generated by the deformations of the substrates. The surface magnetoelastic waves of Rayleigh type, decaying exponentially with distance from substrates surfaces, are studied. For a plane harmonic wave the dispersion equation is derived and solved to obtain the coupled wave frequencies. The magnetomechanical coupling effects are investigated in detail and simulations show that the magnetoelastic coupling effect is quite significant when the gap relative thickness is rather small. The existence of two surface gap waves with two different velocities is shown. In superconducting media the constitutive relations of magnetic field and electrical current of primary nondeformed state are given by means of London’s equations.

MATHEMATICAL MODELING OF TEMPERATURE EFFECT ON THE FAN CHART OF MAGNETOABSORPTION SPECTRUM IN SEMICONDUCTORS

2019 ◽  
pp. 104-115
Author(s):  
G. Gulyamov ◽  
U. I. Erkaboev ◽  
A. G. Gulyamov
Keyword(s):  
Mathematical Modeling ◽  
Magnetic Field ◽  
Temperature Dependence ◽  
Density Of States ◽  
Landau Levels ◽  
Joint Density ◽  
Narrow Gap ◽  
Narrow Gap Semiconductors ◽  
Dispersion Law ◽  
The Magnetic Field

The article considers the oscillations of interband magneto-optical absorption in semiconductors with the Kane dispersion law. We have compared the changes in oscillations of the joint density of states with respect to the photon energy for different Landau levels in parabolic and non-parabolic zones. An analytical expression is obtained for the oscillation of the combined density of states in narrow-gap semiconductors. We have calculated the dependence of the maximum photon energy on the magnetic field at different temperatures. A theoretical study of the band structure showed that the magnetoabsorption oscillations decrease with an increase in temperature, and the photon energies nonlinearly depend on a strong magnetic field. The article proposes a simple method for calculating the oscillation of joint density of states in a quantizing magnetic field with the non-quadratic dispersion law. The temperature dependence of the oscillations joint density of states in semiconductors with non-parabolic dispersion law is obtained. Moreover, the article studies the temperature dependence of the band gap in a strong magnetic field with the non-quadratic dispersion law. The method is applied to the research of the magnetic absorption in narrow-gap semiconductors with nonparabolic dispersion law. It is shown that as the temperature increases, Landau levels are washed away due to thermal broadening and density of states turns into a density of states without a magnetic field. Using the mathematical model, the temperature dependence of the density distribution of energy states in strong magnetic fields is considered. It is shown that the continuous spectrum of the density of states, measured at the temperature of liquid nitrogen, at low temperatures turns into discrete Landau levels. Mathematical modeling of processes using experimental values of the continuous spectrum of the density of states makes it possible to calculate discrete Landau levels. We have created the three-dimensional fan chart of magneto optical oscillations of semiconductors with considering for the joint density of energy states. For a nonquadratic dispersion law, the maximum frequency of the absorbed light and the width of the forbidden band are shown to depend nonlinearly on the magnetic field. Modeling the temperature  dependence allowed us to determine the Landau levels in semiconductors in a wide temperature spectrum. Using the proposed model, the experimental results obtained for narrow-gap semiconductors are analyzed. The theoretical results are compared with experimental results.

Magnetic field enhanced luminescence in diluted narrow gap Hg1-xMnxTe

1996 ◽  
Vol 37 (4) ◽  
pp. 517-523 ◽  
Author(s):  
Yu.I. Mazur ◽  
A.S. Rakitin ◽  
G.G. Tarasov ◽  
V. Jähnke ◽  
J.W. Tomm
Keyword(s):  
Magnetic Field ◽  
Narrow Gap ◽  
Enhanced Luminescence

scholarly journals Interpolation of externally-caused magnetic fields over large sparse arrays using Spherical Elementary Current Systems

2010 ◽  
Vol 28 (9) ◽  
pp. 1795-1805 ◽  
Author(s):  
S. A. McLay ◽  
C. D. Beggan
Keyword(s):  
Magnetic Field ◽  
External Field ◽  
Current System ◽  
Electrical Current ◽  
Ionospheric Currents ◽  
Large Area ◽  
Physically Based ◽  
Subsurface Current ◽  
Current Systems ◽  
The Magnetic Field

Abstract. A physically-based technique for interpolating external magnetic field disturbances across large spatial areas can be achieved with the Spherical Elementary Current System (SECS) method using data from ground-based magnetic observatories. The SECS method represents complex electrical current systems as a simple set of equivalent currents placed at a specific height in the ionosphere. The magnetic field recorded at observatories can be used to invert for the electrical currents, which can subsequently be employed to interpolate or extrapolate the magnetic field across a large area. We show that, in addition to the ionospheric currents, inverting for induced subsurface current systems can result in strong improvements to the estimate of the interpolated magnetic field. We investigate the application of the SECS method at mid- to high geomagnetic latitudes using a series of observatory networks to test the performance of the external field interpolation over large distances. We demonstrate that relatively few observatories are required to produce an estimate that is better than either assuming no external field change or interpolation using latitudinal weighting of data from two other observatories.

Calculations of Bulk and Surface Magnetic Polaritons in Modulated Antiferromagnetic / Non-Magnetic Superlattices

1993 ◽  
Vol 313 ◽  
Author(s):  
Fred Lacy ◽  
Ernest L. Carter ◽  
Steven L. Richardson
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Spin Waves ◽  
Theoretical Research ◽  
Relative Thickness ◽  
Magnetic Superlattices ◽  
Magnetic Spin ◽  
Magnetic Polaritons

ABSTRACTRecent advances in molecular beam epitaxy have renewed research on the physics of artificially structured magnetic superlattices. In particular, there has been much theoretical research on the propagation of magnetic spin waves or magnetic polaritons in magnetic superlattices.1 In this work, we have studied the effect of modulating both the period of an antiferromagnetic/non-Magnetic semi-infinite superlattice and the relative thickness of its individual layers to see how the dispersion relationships co (k) for bulk and surface magnetic polaritons are effected. We have also calculated the effect of an external magnetic field on (u (k) and our calculation goes beyond the magnetostatic approximation by taking retardation effects into account.

Modeling and Designing an Intelligent Controller using Bond Graph for a Satellite Controlled by Magnetic Actuators

2012 ◽  
Vol 2 (1) ◽  
pp. 72-90 ◽  
Author(s):  
Majid Habibi ◽  
Alireza B. Novinzadeh
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Electrical Current ◽  
Bond Graph ◽  
Control Logic ◽  
State Equations ◽  
Magnetic Actuators ◽  
Advantages And Disadvantages ◽  
Aerospace Technology ◽  
Short Time

Satellite state control has always been an important topic in aerospace technology. Because it is required that when the satellite is stationary in orbit, it would be directed to a special object and this task should be performed in a situation where there isn’t access to the satellite. This task is performed using various technologies and one of these is the use of magnetic actuators. Magnetic actuators use mechanical torque that is resulted by interaction of electrical current of coils in the satellite and the earth’s magnetic field. The satellite is subjected to such disturbance torques, thus corrupting the direction of the satellite. This method has its advantages and disadvantages. Its drawback is that the magnetic torque is produced only perpendicular to the direction of the magnetic field and the axis of the coil. This paper models a satellite having magnetic actuators using bond graph, and finds out its state equations, and then constructs the control logic that is needed for its control. A model of three dimensional attitude maneuvers and magnetic systems using bond graph is described. The actuators are tuned using the method of particle swarm optimization (PSO). It is observed that using this method a small satellite reaches to the desired angle in a short time and becomes stationary.

scholarly journals The Terahertz Controlled Duplex Isolator: Physical Grounds and Numerical Experiment

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Konstantin Vytovtov ◽  
Said Zouhdi ◽  
Rostislav Dubrovka ◽  
Volodymyr Hnatushenko
Keyword(s):  
Oblique Incidence ◽  
Faraday Effect ◽  
Harmonic Wave ◽  
Analytical Form ◽  
Electromagnetic Properties ◽  
Anisotropy Axis ◽  
Dual Frequency ◽  
Plane Harmonic Wave ◽  
Axis Orientation ◽  
First Time

Electromagnetic properties of an anisotropic stratified slab with an arbitrary orientation of the anisotropy axis under an oblique incidence of a plane harmonic wave are studied. The dependence of the eigenwave wavenumbers and the reflection coefficient on an anisotropy axis orientation and frequency is investigated. For the first time, the expression for the translation matrix is obtained in the compact analytical form. The controlled two-way dual-frequency (duplex) isolator based on the above described slab is presented for the first time. It is based on the properties of the anisotropic structure described here but not on the Faraday effect.

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