Magnetism at the Mesoscale: Harnessing Competing Interactions

Modern magnetic heterostructures are key components in many application concepts relevant to information technologies. At the same time, magnetic interactions give rise to a surprising amount of complexity due to the fact that both static and dynamic magnetic properties are governed by competing short-range exchange interactions and long-range dipolar coupling. Synthesizing magnetic materials and heterostructures with tailored properties allows one to take advantage of competing interactions spanning many-length scales, which can be probed with advanced spectroscopy and microscopy and modeled with micromagnetic simulations. To illustrate, Hoffman first will focus on the manipulation of spin waves, which are the fundamental excitations of a magnetically ordered system. Local magnetic fields generated from charge currents can control the propagation of spin waves, enabling their guidance through curved waveguides and the switching of spin waves between multiple waveguides. Second, he will discuss magnetic structures called skyrmions. These magnetic configurations have a distinct topology, which result in quasi-particle-like behavior of individual skyrmions. He will show how the combination of charge currents and spin-orbit coupling (spin Hall effects) can be used to electrically generate and manipulate skyrmions at room temperature.

Host: Carlo Segre, Duchossois Leadership Professor of Physics