Artemchuk P. Detection and processing of electromagnetic signals of radio, microwave and terahertz bands in spintronic magnetic nanostructures

The dissertation is devoted to the investigation of processes of detection and processing of electromagnetic signals of radio, microwave, and terahertz (THz) bands in spintronic magnetic nanostructures, and investigate the possibility of energy harvesting of such signals using devices based on spintronic magnetic nanostructures. Detection of electromagnetic signals and their processing are the key operations performed in modern electronic devices and information and communication systems. At the same time, even an insignificant increase in the efficiency of these operations can lead to significant improvement of technical parameters of correspondent devices and systems. This stimulates the continuous search for new, more effective principles of detection and processing of electromagnetic signals, improvement of existing principles, development of the element base, etc. Spintronics systems using transfer of the spin-torque instead of transfer of an electric charge can be alternative to semiconductor systems of detection and processing of electromagnetic signals. Such systems have better energy efficiency, their state can be controlled by allying current and/or magnetic field, they are8 more resistant to electromagnetic interference, ionizing radiation, etc. One of the most known spintronic devices that is easy to realize in practice is a spintronic microwave nanodetector (SMND). Such detectors have been actively investigated for the last 10–15 years and it was shown that their volt-watt sensitivity can exceed ∼ 1 V/W for passive systems, 220 V/W for SMNDs controlled by a direct current (this is significantly higher than the sensitivity of the best Schottky diodes), which makes SMND a new perspective type of a detector of electromagnetic signals. The drawback of existing SMND is quite low operation frequencies (typically 1 − 30 GHz), which is because of the use of ferromagnetic (FM) materials mostly in such systems. To get rid of this drawback a possibility of creation of a detector based on the tunneling junction utilizing antiferromagnetic (AFM) materials (antiferromagnetic tunnel junction, shortly ATJ), having typical operation frequencies reaching ∼ 0.1 − 10 THz has been analyzed.