Electrical Characteristics Of The Quantitative Magnetic Near-field Microwave Microscopy

This thesis has four chapters: the first chapter reviews the related backgrounds of the magneto-electric materials and the scanning evanescent microwave microscopy. The following three chapters describe our work on the new applications of the scanning evanescent microwave microscope, including the quantitative microscopy of the dielectric constant of thin films in the second chapter, the quantitative microscopy of the nonlinear dielectric constant in the third chapter, and the quantitative microscopy of the magneto-electric coefficient in the fourth chapter based on the previous two chapters.In chapter one, the basic concept, history, classification, and recent progress of the magneto-electric materials are introduced. Thereafter, the history, system design, mechanism, fundamental quantitative microscopy theory, and applications of the scanning evanescent microwave microscopy, which the magneto-electricity measurement technique developed in this thesis is based on, are reviewed. Finally, the research outline and its significance of this thesis are explained.In chapter two, the quantitative evanescent microwave microscopy of the dielectric constant of thin films using a recursive image charge approach is described. Firstly, numerical simulation of the interaction between the tip of the microscope and the bulk material is performed by using finite element analysis. Unfortunately, the nodes required for an accurate simulation of the rapidly amplitude varying evanescent electromagnetic field are huge. Consequently, the memory and computation resources of a personal computer are inadequate for routine applications. Furthermore, our analysis shows that fatal error could be incurred in the thin film case, indicating that the finite element analysis is not suitable for the simulation of the evanescent microwave inside thin films. Then, a recursive image charge approach is introduced to represent the interaction between the tip, film, and substrate. An efficient recursion-to-circulation algorithm is then developed to sum the huge total image charges produced in the image process with a reasonable precision. Finally, the total image charges on the tip (which is proportional to the resonant frequency shift of the...