Pressure and Temperature Effects on the Magnetic Properties of Donor Impurities in a GaAs/AlGaAs Quantum Heterostructure Subjected to a Magnetic Field

2021 ◽  
Vol 14 (3) ◽  
pp. 231-238
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Uniform Magnetic Field ◽  
Growth Direction ◽  
Exact Diagonalization ◽  
Donor Impurity ◽  
Diagonalization Method ◽  
Exact Diagonalization Method ◽  
Pressure And Temperature Effects ◽  
The Magnetic Field

Abstract: The exact diagonalization method has been used to solve the effective-mass Hamiltonian of a single electron confined parabolically in the GaAs/AlGaAs quantum heterostructure, in the presence of a donor impurity and under the effect of an applied uniform magnetic field. The donor impurity is located at distance (d) along the growth direction which is perpendicular to the motion of the electron in a two-dimensional heterostructure layer. We have investigated the dependence of the magnetization (M) and magnetic susceptibility (χ) of a GaAs/AlGaAs quantum heterostructure nanomaterial on the magnetic field strength (ω_c), confining frequency (ω_o), donor impurity position (d), pressure (P) and temperature (T). Keywords: Exact diagonalization, Donor impurity, Magnetic field, Magnetization, Magnetic susceptibility, Pressure and temperature.

The magnetization and magnetic susceptibility of GaAs Gaussian quantum dot with donor impurity in a magnetic field

2019 ◽  
Vol 33 (34) ◽  
pp. 1950422 ◽  
Author(s):  
Mohammad Elsaid ◽  
Mohamoud Ali ◽  
Ayham Shaer
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Quantum Dot ◽  
Theoretical Study ◽  
Donor Impurity ◽  
Confinement Potential ◽  
Potential Depth ◽  
Diagonalization Method ◽  
Electron Quantum ◽  
Exact Diagonalization Method

We present a theoretical study to investigate the effect of donor impurity on the magnetization (M) and the magnetic susceptibility [Formula: see text] of single electron quantum dot (QD) with Gaussian confinement in the presence of a magnetic field. We solve the Hamiltonian of this system, including the spin, by using the exact diagonalization method. The ground state binding energy (BE) of an electron has been shown as a function of QD radius and confinement potential depth. The behaviors of the magnetization and the magnetic susceptibility of a QD have been studied as a function of temperature, confinement potential depth, quantum radius and magnetic field. We have shown the effect of donor impurity on the magnetization and magnetic susceptibility curves of Gaussian quantum dot (GQD).

scholarly journals On-demand Ferrofluid Droplet Formation With Non-linear Magnetic Permeability in the Presence of a Non-uniform Magnetic Field

2021 ◽  
Author(s):  
Mohamad Ali Bijarchi ◽  
Mohammad Yaghoobi ◽  
Amirhossein Favakeh ◽  
Mohammad Behshad Shafii
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Uniform Magnetic Field ◽  
Maxwell Equations ◽  
Droplet Diameter ◽  
Droplet Formation ◽  
Bond Number ◽  
On Demand ◽  
Drop On Demand ◽  
The Magnetic Field

Abstract The magnetic actuation of ferrofluid droplets offers an inspiring tool in widespread engineering and biological applications. In this study, the dynamics of ferrofluid droplet generation with a Drop-on-Demand feature under a non-uniform magnetic field is investigated by multiscale numerical modeling. Langevin equation is assumed for ferrofluid magnetic susceptibility due to the strong applied magnetic field. Large and small computational domains are considered. In the larger domain, the magnetic field is obtained by solving Maxwell equations. In the smaller domain, a coupling of continuity, Navier Stokes, two-phase flow, and Maxwell equations are solved by utilizing the magnetic field achieved by the larger domain for the boundary condition. The Finite volume method and coupling of level-set and Volume of Fluid methods are used for solving equations. The droplet formation is simulated in a two-dimensional axisymmetric domain. The method of solving fluid and magnetic equations is validated using a benchmark. Then, ferrofluid droplet formation is investigated experimentally and the numerical results are in good agreement with the experimental data. The effect of 12 dimensionless parameters including the ratio of magnetic, gravitational, and surface tension forces, the ratio of the nozzle and magnetic coil dimensions, and ferrofluid to continuous-phase properties ratios are studied. The results showed that by increasing the magnetic Bond number, gravitational Bond number, Ohnesorge number, dimensionless saturation magnetization, initial magnetic susceptibility of ferrofluid, the generated droplet diameter reduces, whereas the formation frequency increases. The same results were observed when decreasing the ferrite core diameter to outer nozzle diameter, density, and viscosity ratios.

scholarly journals The Effects of Pressure and Temperature on the Magnetic Susceptibility of Semiconductor Quantum Dot in A Magnetic Field

2017 ◽  
Vol 9 (1) ◽  
pp. 77 ◽  
Author(s):  
Faten BZOUR ◽  
Mohammad K. ELSAID ◽  
Ayham SHAER
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Quantum Dot ◽  
Theoretical Study ◽  
External Pressure ◽  
Diagonalization Method ◽  
Electron Quantum ◽  
Exact Diagonalization Method ◽  
Good Agreement ◽  
Parabolic Quantum Dot

In this work, we present a theoretical study of the magnetic susceptibility (x of two-electron GaAs parabolic quantum dot (QD) under the combined effects of external pressure, temperature and magnetic field. We used the exact diagonalization method to obtain the eigenenergies by solving the two electron quantum dot Hamiltonian taking into account the dependence of the effective mass and dielectric constant on the hydrostatic pressure and temperature. The pressure and temperature show significant effects on the calculated QD spectra. Next, we investigate the behavior of the magnetization of a quantum dot as a function of external pressure, temperature, confining frequency and magnetic field. The singlet-triplet transitions in the ground state of the quantum dot spectra and the corresponding jumps in the magnetic susceptibility spectra have been shown. The comparison shows that our results are in very good agreement with the reported works.

The electronic states and magnetization of coupled AlGaAs/GaAs quantum dots in magnetic fields

2018 ◽  
Vol 32 (02) ◽  
pp. 1850011 ◽  
Author(s):  
Eshtiaq Hijaz ◽  
Mohammad K. Elsaid
Keyword(s):  
Magnetic Field ◽  
Quantum Dots ◽  
Ground State ◽  
Theoretical Study ◽  
Electronic States ◽  
Exact Diagonalization ◽  
Interacting Electrons ◽  
Diagonalization Method ◽  
Exact Diagonalization Method ◽  
Good Agreement

We present a theoretical study of electronic states and magnetization of two interacting electrons confined in coupled quantum dots (CQDs) presented in a magnetic field. We obtain the eigenenergies of the CQD by solving the relative two-dimensional (2D) Hamiltonian using the combined variational–exact diagonalization method. The dependence of magnetization on temperature, magnetic field strength, confining frequency and barrier height has been investigated. We have shown the singlet–triplet transitions in the ground state of the CQD spectra and the corresponding jumps in the magnetization curves. The comparisons show that our results are in very good agreement with the reported works.

scholarly journals A Rapid Magnetofluidic Micromixer Using Diluted Ferrofluid

2016 ◽  
Author(s):  
Majid Hejazian ◽  
Nam-Trung Nguyen
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
External Magnetic Field ◽  
Uniform Magnetic Field ◽  
Body Force ◽  
Low Cost ◽  
Magnetic Field Gradient ◽  
Mixing Efficiency ◽  
Biological Assays ◽  
The Magnetic Field

Effective and rapid mixing is essential for various chemical and biological assays. The present work reports a simple and low-cost micromixer based on magnetofluidic actuation. The device takes advantage of magnetoconvective secondary flow, a bulk flow induced by an external magnetic field, for mixing. A paramagnetic stream of diluted ferrofluid and a non-magnetic stream are introduced to a straight microchannel. A permanent magnet placed next to the microchannel induced a non-uniform magnetic field. The magnetic field gradient and the mismatch in magnetic susceptibility between the two streams create a body force, which leads to rapid and efficient mixing. The micromixer reported here could achieve a high throughput and a high mixing efficiency of 90 % in a relatively short microchannel.

The stability of viscous flow in a curved channel in the presence of a magnetic field

1961 ◽  
Vol 264 (1317) ◽  
pp. 155-164 ◽  
Keyword(s):  
Magnetic Field ◽  
Viscous Flow ◽  
Uniform Magnetic Field ◽  
Axial Direction ◽  
Electrical Conductor ◽  
Curved Channel ◽  
Coaxial Cylinders ◽  
Transverse Pressure ◽  
The Stability ◽  
The Magnetic Field

The stability of viscous flow between two coaxial cylinders maintained by a constant transverse pressure gradient is considered when the fluid is an electrical conductor and a uniform magnetic field is impressed in the axial direction. The problem is solved and the dependence of the critical number for the onset of instability on the strength of the magnetic field and the coefficient of electrical conductivity of the fluid is determined.

scholarly journals Spin-1/2 Particles under the Influence of a Uniform Magnetic Field in the Interior Schwarzschild Solution

Universe ◽  
2021 ◽  
Vol 7 (12) ◽  
pp. 467
Author(s):  
Fayçal Hammad ◽  
Alexandre Landry ◽  
Parvaneh Sadeghi
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Total Mass ◽  
Uniform Magnetic Field ◽  
Energy Levels ◽  
Relativistic Wave Equation ◽  
Relativistic Wave ◽  
Schwarzschild Solution ◽  
Relativistic Regime ◽  
The Magnetic Field

The relativistic wave equation for spin-1/2 particles in the interior Schwarzschild solution in the presence of a uniform magnetic field is obtained. The fully relativistic regime is considered, and the energy levels occupied by the particles are derived as functions of the magnetic field, the radius of the massive sphere and the total mass of the latter. As no assumption is made on the relative strengths of the particles’ interaction with the gravitational and magnetic fields, the relevance of our results to the physics of the interior of neutron stars, where both the gravitational and the magnetic fields are very intense, is discussed.

Numerical analysis of the magnetic field for arbitrary magnetic susceptibility distributions in 3D

1994 ◽  
Vol 12 (1) ◽  
pp. 101-107 ◽  
Author(s):  
R. Bhagwandien ◽  
M.A. Moerland ◽  
C.J.G. Bakker ◽  
R. Beersma ◽  
J.J.W. Lagendijk
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Numerical Analysis ◽  
The Magnetic Field

scholarly journals Deformation of a magnetic liquid drop in an applied non-stationary uniform magnetic field

2018 ◽  
Vol 185 ◽  
pp. 09006
Author(s):  
Alexander Tyatyushkin
Keyword(s):  
Magnetic Field ◽  
Reynolds Number ◽  
Steady State ◽  
Uniform Magnetic Field ◽  
Liquid Drop ◽  
Magnetic Liquid ◽  
Stationary Approximation ◽  
The Magnetic Field

Small steady-state deformational oscillations of a drop of magnetic liquid in a nonstationary uniform magnetic field are theoretically investigated. The drop is suspended in another magnetic liquid immiscible with the former. The Reynolds number is so small that the inertia can be neglected. The variation of the magnetic field is so slow that the quasi-stationary approximation for the magnetic field and the quasi-steady approximation for the flow may be used.

Textured Beta-Sialon:Eu2+ Phosphor Deposits Fabricated by Electrophoretic Deposition (EPD) Process within a Strong Magnetic Field: Preparation Process and Photoluminescence (PL) Properties Depending on Orientation

2015 ◽  
Vol 654 ◽  
pp. 268-273
Author(s):  
Chen Ning Zhang ◽  
Tetsuo Uchikoshi ◽  
Li Hong Liu ◽  
Benjamin Dierre ◽  
Yu Jin Cho ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Electric Field ◽  
Strong Magnetic Field ◽  
Electrophoretic Deposition ◽  
Intensity Ratio ◽  
Preparation Process ◽  
Crystal Axis ◽  
Chromaticity Coordinates ◽  
The Magnetic Field

Beta-sialon:Eu2+ phosphor deposits were fabricated by electrophoretic deposition (EPD) process within a strong magnetic field (12 T). The direction of the magnetic field was adjusted to be parallel or perpendicular to that of the electric field, that is, vertical-or horizontal setup. The oriented deposits were fabricated by aligning the β-sialon:Eu2+ particles along the higher magnetic-susceptibility c-crystal axis (a, b-crystal plane). For the case of vertically-setup magnetic field, the oriented deposit aligned along the c-axis possessed higher relative deposit density than the randomly fabricated deposit, as a result, varying the intensity ratio of emission and transmitted excitation, and therefore, presenting different chromaticity coordinates; for the case of horizontally-setup magnetic field, photoluminescence (PL) intensities of the deposits oriented along c-axis were significantly improved by comparing with those of the randomly-oriented ones.

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