The magnetization dynamics of Co(5 nm)/Ru/Co(5 nm) trilayers with Ru thicknesses from 0.3–0.6 nm is experimentally and theoretically investigated. The coupling between the Co layers is antiferromagnetic (AFM) and yields a stable AFM domain structure with frozen domain walls. Comparing high-resolution magnetic force microscopy (MFM) and pump-probe measurements, we analyze the behavior of the films for different field-strength regimes. For moderate magnetic fields, pump-probe measurements provide dynamic characterization of the coupled precessional modes in the GHz range. The dynamics at small fields is realized by the pinning of AFM domain walls at inhomogeneities. The MFM images yield a domain-wall width that varies from about 150–60 nm. This behavior is explained in terms of a micromagnetic local-anisotropy model.
Li, Zhen, Ralph Skomski, Sy-Hwang Liou, Steven Michalski, Mircea Chipara, and Roger D. Kirby. 2011. “Magnetization Precession and Domain-Wall Structure in Cobalt-Ruthenium-Cobalt Trilayers.” Journal of Applied Physics 109 (7): 07C113. https://doi.org/10.1063/1.3540406.
Journal of Applied Physics