Argonne National Laboratory

Unconventional topological spin structure in coupled magnetic discs

March 12, 2012

Argonne's Materials Science Division researchers have fabricated an artificially-confined system of magnetic discs coupled antiferromagnetically through a spacer layer, and demonstrated for the first time that this system forms an unconventional topological spin structure. This spin structure and its behavior were directly observed using the unique aberration-corrected Lorentz transmission electron microscope at Argonne using in situ experiments. The experiments together with micromagnetic simulations led to an understanding of the formation and stability of this spin structure, which closely resembles the exotic topological structure known as a “meron.” This understanding is important to control and predict the behavior of nanostructured magnetic materials, which are key to the next generation of magnetic storage and memory applications. Additionally, this research also opens new opportunities for the study of interesting fundamental physics of critical phenomena and related topological states directly at room temperature.

Reference: C. Phatak, A. K. Petford-Long, and O. Heinonen, “Direct Observation of Unconventional Topological Spin Structure in Coupled Magnetic Discs“, Physical Review Letters, 108, 067205 (2012).