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Ferromagnetic medium diluted magnetic semiconductor spin-dependent optical and electrical properties

Author: BaiLiHui
Tutor: ShenXueChu；ChenZhangHai；HuCanMing
School: Fudan University
Course: Optics
Keywords: External magnetic field Ferromagnetic resonance Spin waves Diluted magnetic semiconductors Detector Exchange interaction Magnetic dynamics Saturation magnetization Dipole interaction Permalloy
CLC: O482.5
Type: PhD thesis
Year: 2008
Downloads: 322
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Abstract

This article focuses on the nature of the electron spin and charge transport medium, which is the core issue of spintronics research. The medium external magnetic field, the electron energy levels Zeeman splitting occurs, the spin-polarized carrier transition and transfer. We use the electrical and optical methods to study the nature of the carrier spin polarization in the ferromagnetic diluted magnetic semiconductor medium. The main work is as follows: We experimentally studied the relationship of the magnetic dynamic process and the charge-transporting observed to occur in the medium ferromagnet photovoltage effect. It is a medium body effect, the physical origin of the microwave-driven magnetic moment precession with the coupling of the microwave current. We thus developed a theory of spin rectification effect, a good explanation of the experimentally observed to ferromagnetic medium photovoltage, photocurrent, light resistance phenomenon. The discovery of the spin rectification effect provides a new way of thinking for the use of the electrical method to measure the magnetic dynamics in ferromagnetic media (such as ferromagnetic resonance and spin wave). Based on this principle, we have in-depth discussion of the process the ferromagnetic media of various sizes in different outer magnetic field configuration of magnetic dynamics. Combined Landau of Li Fu Xici Gilbert equations and boundary conditions of Maxwell's equations, we systematically expounded all kinds of spin-wave mode dynamics theory to explain the uneven static magnetic field under special bit-shaped area in local mode and surface static the development transformation between the magnetic mode. Based on the spin rectification effect, we have designed and fabricated a new detection radiofrequency magnetic vector detector the existing loop coil magnetic field detectors, the new detector is able to detect microwave magnetic field vector, and achieve subwavelength dimensions the inside of the microwave detection. From the theoretical and experimental point of view to verify that this works and the quality of the detector. The second part of this paper is mainly to study the excitation of spin-polarized electrons in diluted magnetic semiconductors, transfer and composite motor behavior, it is spintronics Another important research direction. Magneto-optical spectroscopic methods to study the spin polarization of carriers in diluted magnetic semiconductor level splitting of the external magnetic field behavior, experimental concept Chase Man effect caused by spin-polarized carrier and spin polarization of carriers in the transfer of energy levels and spatial behavior. Which provides a good basis for the design of of spintronics new devices for the semiconductor process.

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