Professor of Physics Xuemei M. Cheng and Alums Co-Author Article, Aug. 2022

Topological Spin Memory of Antiferromagnetically Coupled Skyrmion Pairs in Co/Gd/Pt Multilayers

Authors: Xiao Wang, Ph.D. '20; Alexandra R. Stuart; Mitchell S. Swyt; Carla M. Quispe Flores; Andy T. Clark, Ph.D. '22; Adzo Fiagbenu; Rajesh V. Chopdekar; Pavel N. Lapa; Zhuyun Xiao '15; Dava Keavney; Richard Rosenberg; Michael Vogel; John E. Pearson; Suzanne G. E. te Velthuis; Axel Hoffman; Kristen S. Buchanan; Xuemei M. Cheng

Source: Physical Review Materials, Volume: 6, Issue: 8, DOI: 10.1103/PhysRevMaterials.6.084412, August 2022

Type of Publication: Journal Article

Abstract: Antiferromagnetically (AFM) coupled skyrmions offer potential advantages for spintronic devices, including reduced dipolar fields that may enable smaller skyrmion sizes and a reduction of the skyrmion Hall effect. However, the topological stability of AFM-coupled skyrmions subjected to dramatic spin deformation through low-temperature cycling has not been investigated. Here we report the discovery of a topological spin memory effect for AFM-coupled skyrmion pairs in [Co/Gd/Pt]₁₀ multilayered films. Photoemission electron microscopy imaging shows that bubble skyrmions in the multilayer that are stable at room temperature evolve into complex in-plane spin textures as the temperature is lowered and reform completely when the sample is warmed back up. Simulations demonstrate that Dzyaloshinskii-Moriya interactions play a key role in this spin memory effect, and furthermore reveal that the topological charge is preserved throughout the dramatic spin texture rearrangement and recovery. These results highlight a key aspect of topological protection—the preservation of the topological properties under continuous deformation—and also provide a promising avenue for information encryption and recovery.

Xuemei M. Cheng is dean of graduate studies and professor of physics.