Transmission of the Magnetic Field to Nanoscale and Investigation of Its Spintronic Effects.

Abstract

While we are gradually approaching the fundamental limit of integrated circuits in classic electronics, smaller devices and new carriers for the information and signals are still in demand. There is also a problem of designing energy efficient electronics. One of the common issues in this area is how to manipulate microwave at very small scales, i.e., nanometers. Currently the fabrication of nanostructured materials either physically or in composition, and of nanoscale objects such as nanoparticles, nanotubes and nanowires is performed routinely in many research laboratories and private companies. In addition, the physical properties of these structures and objects (mechanical, electrical, magnetic etc.) are also relatively well understood in the two extreme frequency ranges corresponding to the low frequency range (up to 100 MHz) and to the optical frequency range (above THz). However, for the microwave frequency range 1 GHz-100 GHz most of these properties at the nanoscale are still to be investigated. The main reason for this situation has been the lack of enough development of theoretical and experimental techniques and tools to investigate this interaction at the nanoscale. In this thesis, different approaches for characterization of nanostructures at microwave frequencies., namely, Atomic Force Microscope (AFM), the Electrostatic Force Microscope (EFM) and the Scanning Microwave Microscope (SMM) were performed. Before going deeply to the practice and simulation the basic principles of quantum mechanics were considered to understand the processes happening at the end of the tip, probe or any nanoscale source in free space. This theory is well-connected to the feeding device optimization study presented as it is shown Chapter 3 where the numerical simulation of the single electron wave function is shown. It has provided the first contribution of this thesis where the improvement of the AFM tip simulation is shown. The second objective of this thesis was to determine how the microwaves propagate, reflect or are transmitted from the nanoscale object. The optimization study results of the feeding device for a hall bar structure were presented in order to do that. The properties of this device were investigated theoretically and numerically. The optimized structure then will be prepared for the fabrication, i.e., the mask for electronbeam lightning will be presented.