TRR 360 Seminar:

Active Magnets

Achim Rosch

Active Magnets

Prof. Dr. Achim Rosch

Institute for Theoretical Physics, University of Cologne

Active matter encompasses many-particle systems composed of self-propelled units, such as flocks of birds or schools of fish. We ask whether similar physics can emerge in condensed-matter systems driven out of equilibrium, for example by radiation. Focusing on magnetic systems with Goldstone-like modes that can be activated by weak external stimuli, we study a ferrimagnet subject to a weak oscillating field. In our model, domain walls acquire active motion in a direction selected by spontaneous symmetry breaking. This leads to qualitatively new dynamics: long-range order develops with remarkable efficiency and is highly robust against noise. We show that these properties originate from a novel form of dynamical frustration induced by the dynamics of Goldstone modes.