自旋电子学与新型光电探测技术的研究

发布时间：2018-04-29 19:55

本文选题：自旋电子学 + 微波　；参考：《中国科学院研究生院（上海技术物理研究所）》2014年博士论文

【摘要】：类比于半导体光电探测技术中电子能级分裂形成能带结构后对光子的光电压探测，本文提出：利用外磁场作用下铁磁材料内剩余磁矩能级分裂形成的能级结构对微波光子的吸收，，制成可集成化的微波探测器，实现对微波的光电探测。本文所基于的材料特性是铁磁材料的各向异性磁电阻效应，由于该效应，微波的磁场分量改变材料内磁矩的方向并形成动态电阻，动态电阻与微波的电分量在材料内诱导产生的交变电流耦合形成整流直流电压，即获得光电压输出。与传统射频电路对微波的探测相比，该方法有效避免了微波对传输线的相位、幅度敏感性，并且可进行器件的集成化。利用该微波探测器及其构成的微波成像系统，实现了相位分辨的微波段介质介电常数测量及介质、金属的近场微波成像。在对物理背景的介绍中，本文依次进行了铁磁性、各向异性磁电阻效应、自旋进动、铁磁共振及自旋整流的论述，从自旋电子学里对材料的研究转入到对微波光电转化的研究。自旋整流效应是本文所用微波探测机制的物理基础，并且类比于迈克耳逊干涉仪，利用相干的微波在铁磁材料内整流过程中的干涉效应可以实现对相干微波的相位分辨探测。以此搭建的自旋电子学迈克耳逊干涉仪可以进行自旋/磁矩驰豫的自旋动力学研究，也可以用于幅度与相位分辨微波成像系统。在近场微波成像系统中，通过进行微波透过介质后的相位、幅度的测量反演出介质相对于空气的介电性质并且计算出介质的介电常数；对于微波段的亚波长结构，利用近场微波成像系统进行了相位分辨或幅度分辨成像并得到亚波长结构信息，成像实验在理想介质、强吸收性介质、强反射性金属结构上都获得了实现。
[Abstract]:Analogous to the photovoltage detection of photons after the electron energy level splits into a band structure in semiconductor photoelectric detection technology, In this paper, it is proposed that an integrated microwave detector can be fabricated by using the energy level structure of the residual magnetic moment in ferromagnetic material to absorb the microwave photons, and to realize the photoelectric detection of the microwave. The material characteristic of this paper is the anisotropic magnetoresistance effect of ferromagnetic material. As a result of this effect, the magnetic field component of microwave changes the direction of magnetic moment in the material and forms the dynamic resistance. The alternating current induced by the dynamic resistor and the microwave component in the material is coupled to form the rectified DC voltage, that is, the output of the photovoltage is obtained. Compared with the traditional RF circuit, this method can effectively avoid the phase and amplitude sensitivity of the microwave transmission line, and can integrate the devices. Using the microwave detector and the microwave imaging system, the phase resolved microwave dielectric constant measurement and near-field microwave imaging of metal and dielectric are realized. In the introduction of physical background, ferromagnetism, anisotropic magnetoresistance effect, spin precession, ferromagnetic resonance and spin rectifier are discussed in turn. The spin rectification effect is the physical basis of the microwave detection mechanism used in this paper. Compared with the Michelson interferometer, the phase resolution detection of coherent microwave can be realized by using the interference effect of coherent microwave in the rectifying process of ferromagnetic material. The spin electron Michelson interferometer can be used to study spin dynamics of spin / magnetic moment relaxation, and can also be used in amplitude and phase resolved microwave imaging system. In a near-field microwave imaging system, the dielectric properties of the reverse medium relative to air are measured by the phase of the microwave passing through the medium and the dielectric constant of the medium is calculated; for the subwavelength structure of the microwave segment, Phase resolution or amplitude resolution imaging is carried out by using near field microwave imaging system and sub-wavelength structure information is obtained. The imaging experiments are realized in ideal medium, strong absorption medium and strong reflective metal structure.
【学位授予单位】：中国科学院研究生院（上海技术物理研究所）
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM271

【共引文献】