Seminars Archive

Terahertz spin dynamics

Abstract
Understanding how spins move at pico- and femtosecond time scales is the focus of much of contemporary research in magnetism. In this talk, I will go through some basic and more advanced concepts in the exciting emerging field of terahertz (THz) magnetism, where electromagnetic radiation in the 0.1-10 THz range, the so-called THz gap, is used to probe or to control spin dynamics at these time scales. I will first give an overview of the fundamentals of the interaction between light and matter at THz frequencies, with focus on magnetic materials of relevance for modern research. I will focus on the use of strong terahertz magnetic fields to drive coherent and incoherent spin dynamics. Then, I will illustrate the design of terahertz metamaterials aimed at locally enhancing the magnetic field component of the radiation, with the goal of realizing table-top “ballistic” magnetization switching, whose spectroscopic and spatial details can be imaged using the ultrafast and coherent x-ray radiation generated at free electron lasers.