Optimization of Semimagnetic Semiconductor-Based Nanostructures for Spintronic Applications

2006 ◽  
Vol 518 ◽  
pp. 35-40
Author(s):  
J. Radovanović ◽  
V. Milanović ◽  
Z. Ikonić ◽  
D. Indjin
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Simulated Annealing Algorithm ◽  
Structural Parameters ◽  
Zeeman Effect ◽  
Parameters Optimization ◽  
Potential Barriers ◽  
Annealing Algorithm ◽  
Electrical Bias ◽  
Spin Filtering

We have analyzed the spin-filtering effects of the electron current in asymmetric ZnSe/Zn1-xMnxSe multilayer structures, under the influence of both an external magnetic field and a bias voltage. In this type of semiconductor systems, conduction band electrons interact with 3d electrons of the magnetic Mn2+ ions. Because of this sp-d exchange interaction, an external magnetic field modulates the effective potential profile seen by spin-up and spin-down electrons, giving rise to a large Zeeman effect. It is found that the degree of spin polarization changes significantly when the electrical bias is switched from forward to reverse, thus the proposed structure displays obvious behavior of spin-filter diode. This originates from the effective “lifting” of the potential for spin-up electrons, which tunnel through actual potential barriers. Structural parameters optimization, with the goal of maximizing the spin-filtering coefficient, was performed by using simulated annealing algorithm. The described effect may be important for designing new tunable spin-based multifunctional semiconductor devices.

Structural Parameters Optimization of Waveform Generator Based on LS-SVM and Simulated Annealing Algorithm

2012 ◽  
Vol 268-270 ◽  
pp. 871-874
Author(s):  
Yu Liang Yang ◽  
Jun Qi Qin ◽  
Chang Chun Di ◽  
Yan Feng Yang
Keyword(s):  
Simulated Annealing ◽  
Simulated Annealing Algorithm ◽  
Regularization Parameter ◽  
Design Method ◽  
Orthogonal Design ◽  
Structural Parameters ◽  
Parameters Optimization ◽  
Waveform Generator ◽  
Sample Data ◽  
Annealing Algorithm

For the structural design problem of waveform generator, selected diameter of rubber block, hardness and thickness of block 1 and block 2 as five design variables. Firstly, adopted orthogonal design method, and built initial sample data. Secondly, adopted LS-SVM to exercise the sample data, and selected regularization parameter and kernel function width of LS-SVM based on QPSO algorithm. Finally, optimized the structural parameters of waveform generator based on simulated annealing algorithm. The research provided a theoretic basis for the design of waveform generator.

scholarly journals Optimized design and performance analysis of a magnetic-field modulated brushless dual-mechanical port motor with Halbach array permanent magnets

2020 ◽  
Vol 12 (9) ◽  
pp. 168781402095775
Author(s):  
Ren He ◽  
Junmin Li
Keyword(s):  
Magnetic Field ◽  
Hybrid Electric Vehicle ◽  
Permanent Magnets ◽  
Structural Parameters ◽  
Torque Ripple ◽  
Parameters Optimization ◽  
Optimized Design ◽  
Operating Characteristics ◽  
Trade Offs ◽  
Halbach Array

In order to develop an electrical continuously variable transmission (E-CVT) to replace mechanical power coupling equipment applied in series-parallel hybrid electric vehicle (HEV), this paper proposes a magnetic-field modulated brushless dual-mechanical port motor with Halbach array permanent magnets, which has a more compact structure. The operating characteristics are analyzed by the lever analogy. It is concluded that the motor can realize the speed and torque decoupling between the engine and the wheel, which meet multi-mode operation requirements for HEV. To realize the multi-objective design of torque output, torque ripple and usage amount of permanent magnets, an optimization scheme combined parameter sensitivity with response surface methodology is adopted. The trade-offs among the optimization objectives are considered, then the key structural parameters and its optimal values are efficiently determined. Based on a two-dimensional model, the electromagnetic performances are simulated and analyzed. The results show that, after the parameters optimization, the no-load back electromotive force (EMF) has better sinusoidal characteristic, and the torque ripples and cogging torque peaks of the motor have been significantly reduced. Furthermore, a prototype motor is tested. The experimental results are consistent with the simulation results, which demonstrates the validity of the proposed structure and parameter optimization method.

scholarly journals Vector magnetic field and vector current density in and around the δ-spot NOAA 10808

2010 ◽  
Vol 6 (S273) ◽  
pp. 338-338 ◽  
Author(s):  
Véronique Bommier ◽  
Egidio Landi Degl'Innocenti ◽  
Brigitte Schmieder ◽  
Bernard Gelly
Keyword(s):  
Magnetic Field ◽  
Current Density ◽  
Simulated Annealing Algorithm ◽  
Zeeman Effect ◽  
Vector Current ◽  
Field Vector ◽  
Line Of Sight ◽  
Line Pair ◽  
Spot Center ◽  
The Magnetic Field

AbstractThe context is that of the so-called “fundamental ambiguity” (also azimuth ambiguity, or 180° ambiguity) in magnetic field vector measurements: two field vectors symmetrical with respect to the line-of-sight have the same polarimetric signature, so that they cannot be discriminated. We propose a method to solve this ambiguity by applying the “simulated annealing” algorithm to the minimization of the field divergence, added to the longitudinal current absolute value, the line-of-sight derivative of the magnetic field being inferred by the interpretation of the Zeeman effect observed by spectropolarimetry in two lines formed at different depths. We find that the line pair Fe I λ 6301.5 and Fe I λ 6302.5 is appropriate for this purpose. We treat the example case of the δ-spot of NOAA 10808 observed on 13 September 2005 between 14:25 and 15:25 UT with the THEMIS telescope. Besides the magnetic field resolved map, the electric current density vector map is also obtained. A strong horizontal current density flow is found surrounding each spot inside its penumbra, associated to a non-zero Lorentz force centripetal with respect to the spot center (i.e., oriented towards the spot center). The current wrapping direction is found to depend on the spot polarity: clockwise for the positive polarity, counterclockwise for the negative one. This analysis is made possible thanks to the UNNOFIT2 Milne-Eddington inversion code, where the usual theory is generalized to the case of a line (Fe I λ 6301.5) that is not a normal Zeeman triplet line (like Fe I λ 6302.5).

scholarly journals Zeeman Effect in Phase Space

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
R. A. S. Paiva ◽  
R. G. G. Amorim ◽  
S. C. Ulhoa ◽  
A. E. Santana ◽  
F. C. Khanna
Keyword(s):  
Magnetic Field ◽  
Perturbation Theory ◽  
Phase Space ◽  
External Magnetic Field ◽  
Hydrogen Atom ◽  
Schrödinger Equation ◽  
Harmonic Oscillator ◽  
Schrodinger Equation ◽  
Zeeman Effect ◽  
Two Dimensional

The two-dimensional hydrogen atom in an external magnetic field is considered in the context of phase space. Using the solution of the Schrödinger equation in phase space, the Wigner function related to the Zeeman effect is calculated. For this purpose, the Bohlin mapping is used to transform the Coulomb potential into a harmonic oscillator problem. Then, it is possible to solve the Schrödinger equation easier by using the perturbation theory. The negativity parameter for this system is realised.

scholarly journals The Parameters Optimization of MCR-WPT System Based on the Improved Genetic Simulated Annealing Algorithm

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Sheng Lu ◽  
Chenyang Zuo ◽  
Changhao Piao
Keyword(s):  
Simulated Annealing ◽  
Simulated Annealing Algorithm ◽  
Global Optimum ◽  
Parameters Optimization ◽  
Selection Strategy ◽  
Local Optimum ◽  
Penalty Function Method ◽  
Genetic Simulated Annealing Algorithm ◽  
Annealing Algorithm ◽  
Optimum Solution

To solve the problem of parameter selection during the design of magnetically coupled resonant wireless power transmission system (MCR-WPT), this paper proposed an improved genetic simulated annealing algorithm. Firstly, the equivalent circuit of the system is analysis in this study and a nonlinear programming mathematical model is built. Secondly, in place of the penalty function method in the genetic algorithm, the selection strategy based on the distance between individuals is adopted to select individual. In this way, it reduces the excess empirical parameters. Meanwhile, it can improve the convergence rate and the searching ability by calculating crossover probability and mutation probability according to the variance of population’s fitness. At last, the simulated annealing operator is added to increase local search ability of the method. The simulation shows that the improved method can break the limit of the local optimum solution and get the global optimum solution faster. The optimized system can achieve the practical requirements.

Transverse Zeeman effect for ions in uniaxial crystals

1976 ◽  
Vol 352 (1668) ◽  
pp. 91-108 ◽  
Keyword(s):  
Magnetic Field ◽  
Rare Earth ◽  
External Magnetic Field ◽  
Optical Spectrum ◽  
Zeeman Effect ◽  
Approximate Symmetry ◽  
Crystal Axis ◽  
Large Intensity ◽  
Intensity Changes ◽  
Point Groups

The theory of the Zeeman effect for ions in crystals at sites of uniaxial symmetry has been developed for intra-configuration transitions with the external magnetic field H perpendicular to the crystal axis c . Variations in the axial optical spectrum that occur when the crystal is rotated about c are described in terms of the types A and B of the upper and lower states involved in the transition. Large intensity changes can occur for ions at sites of D 4 , C 4v or D 2d symmetry for those transitions that appear only in the σ spectrum. Analogous variations can only take place for D 6 , C 6v and D 3h in those cases where H is sufficiently large to mix neighbouring crystal-field states. Other uniaxial point groups are considered as cases of approximate symmetry. The theory is developed with particular reference to U 5+ in zircon, to CoCs 3 Cl 5 , and to the rare-earth ethylsulphates.

scholarly journals Bayesian Model Updating Based on Kriging Surrogate Model and Simulated Annealing Algorithm

2022 ◽  
Vol 2148 (1) ◽  
pp. 012008
Author(s):  
Zenghui Wang ◽  
Hong Yin ◽  
Zhenrui Peng
Keyword(s):  
Simulated Annealing ◽  
Surrogate Model ◽  
Bayesian Model ◽  
Simulated Annealing Algorithm ◽  
Model Updating ◽  
Structural Parameters ◽  
Dynamic Responses ◽  
Monte Carlo Algorithm ◽  
Kriging Surrogate Model ◽  
Annealing Algorithm

Abstract Aiming at the problem of difficulty in selecting the proposal distribution and low computational efficiency in the traditional Markov chain Monte Carlo algorithm, a Bayesian model updating method using surrogate model technology and simulated annealing algorithm is proposed. Firstly, the Kriging surrogate model is used to mine the implicit relationship between the structural parameters to be updated and the corresponding dynamic responses, and the Kriging model that meets the accuracy requirement is used to replace the complex finite element model to participate in the iterative calculation to improve the model updating efficiency. Then, the simulated annealing algorithm is introduced to reorganize the Markov chains from different proposal distributions to obtain high-quality posterior samples, which are used to estimate the parameters posterior distributions. Finally, a space truss structure is used to verify the effectiveness of the proposed method.

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