Research Seminar in Mathematics - Identification of transition paths for the prediction of thermal stability and optimal control of magnetic systems
14 April 2023 13:15 Zoom
Please contact Andrii Dmytryshyn if you have any questions regarding this seminar series.
Speaker
Pavel Bessarab, Linnaeus University, Kalmar.
Zoom-link
Meeting ID: 657 3848 7189
Passcode: 607235
Abstract
The identification of paths that are optimal in some sense is an important problem in many areas of science. In this talk, the focus will be on paths for magnetic transitions. An important example is minimum energy paths (MEPs), paths in configuration space that connect states with different orientation of magnetic moments and lie low on the energy surface. MEPs have maximal statistical weight and, therefore, represent mechanisms of thermally activated transitions. Combined with the development of harmonic transition state theory, MEP calculations make it possible to predict the lifetime of magnetic states at a given temperature. MEPs do not, however, reflect the dynamics and there are other paths that represent minimal energy cost of switching between magnetic states. Such 'optimal control paths' (OCPs) involve rotation of magnetic moments in such a way that the system's internal dynamics aids the magnetic transition. The development of theoretical tools for finding MEPs and OCPs on high-dimensional energy surfaces will be discussed and applications presented where thermal stability of magnetic skyrmions is analyzed and spin-wave assisted magnetization switching in nanowires revealed.
Welcome!