@misc{Mieszczak2021,
title = {Anderson localization of spin waves in magnonic nanostructures},
author = {Szymon Mieszczak},
url = {https://projekty.ncn.gov.pl/index.php?projekt_id=475240},
year = {2021},
date = {2021-12-01},
abstract = {The long-standing paradigm is that computation, data processing, etc. needs to be done by the electric circuit, i.e. it is based on the transport of electrons. The Moore's law refers to the empirical rule which states that the number of transistors in a microchip doubles every two years. This statement approaching the end of the road because of the fundamental bottlenecks of physical origin. Therefore, the further miniaturization of microprocessors is questionable. It naturally raises the question, what next? The prospective solution can be found by the studies in the field of solid state physics.

In order to encode, process and transmit information at the nanoscale, other fundamental characteristics of particles, in addition to the electric charge, can be used. We can use the intrinsic angular momentum of the particle -- the spin. In ferromagnetic materials, spins and related magnetic moments interact with each other in quantum manner (by the so-called exchange interaction) or classically (by a dipole coupling between magnetic moments). The interacting magnetic moments perform an oscillatory and coherent motion. Thanks to this they can transmit information in the form of the so-called spin wave.

Over the last few decades, a new field of research and technology has emerged – magnonics, which is focused on the spin wave propagation in magnetic nanostructures. Spin waves allow high frequency signals to be transmitted at the nanoscale. In magnonics, the nanostructured magnetic material are used to control the spin waves. The modifications of the geometry of the system or its static magnetic configuration take place on a scale from several dozen to several hundred nanometers, corresponding to the length of the spin wavelength. The materials modified in this way have completely new properties. Particularly noteworthy are magnetic systems with the periodic pattering – so called magnonic crystals, where in certain frequency ranges (in so-called frequency gaps) the propagation of spin waves is forbidden.

Research on spin waves in naostructures, including the magnonic crystals, is developing intensively thanks to new experimental techniques as well as the increasing computing power, which in turn has allowed the numerical research on more complex systems. This has enabled many fascinating effects and new phenomena on spin waves to be discovered, opening the way to the numerous applications in the field of information processing. These include typical applications such as transistors and logic gateways, working according the principles of the Boolean computing. However, the waves (including spin waves) can be used for analog processing of the information encoded in wave’s amplitude and phase. The general advantage of this type of calculation is that the results of certain operations on signals in waveform can be obtained in real time. A good example is the Fourier transform of signals or the solution of inhomogenious differential equations, where the inhomogeneous part and the solution are treated as input and output signals. Spin waves are characterized by a number of unique properties such as anisotropic propagation, easily accessible nonlinear dynamics and the ability to control by means of a magnetic field or by the interactions with other types of waves: elastic waves and electromagnetic waves.

Our research are focused on the analysis of spin waves dynamics in one-dimensional magnonic crystals made of ferromagnetic stripes where the disorder has been introduced. It can be done by random change of size or modification of material parameters of these strips. The research hypothesis is based on a common-sense observation that controlling the disturbances of the structure allows for modification of the frequency spectrum of spin waves and control of their location in the magnetic structure. In particular, we intend to show that the introduction of disorder may lead to the so-called Anderson location of spin waves in the system of coupled ferromagnetic stripes.
},
howpublished = {2020},
note = {NCN Etiuda, No. 2020/36/T/ST3/00542, budget: 150 264 PLN},
keywords = {},
pubstate = {published},
tppubtype = {misc}
}