Weakly pinned skyrmion liquid in a magnetic heterostructure
journal contributionposted on 2022-09-21, 14:55 authored by Rhodri Mansell, Yifan Zhou, Kassius Kohvakka, See-Chen Ying, Ken R Elder, Enzo Granato, Tapio Ala-NissilaTapio Ala-Nissila, Sebastiaan van Dijken
Magnetic skyrmions are topologically distinct particles whose thermally activated motion could be used to implement probabilistic computing paradigms. While solid-liquid phase transitions in skyrmion lattices have been demonstrated, the behavior of a skyrmion liquid and the effects of pinning are largely unknown. Here we demonstrate the formation of a weakly pinned skyrmion liquid in a magnetic heterostructure. By inserting a Ru wedge layer at the ferromagnet/heavy metal interface we evaluate the dependence of skyrmion dynamics on the skyrmion size and density. Our experiments demonstrate that the diffusion of skyrmions is largest in dense liquids with small skyrmions. The thermal motion of skyrmions at room temperature easily overcomes the narrow distribution of pinning site energies in the granular film structure, satisfying a key requirement of probabilistic device architectures. Micromagnetic simulations support the findings and also reveal the existence of a thermally activated high-frequency collective oscillation.
Dynamics, topological defects and phase transitions in two-dimensional systems.
São Paulo Research FoundationFind out more...
Academy of Finland QTF CoE Grant No. 312298
- Mathematical Sciences
Published inPhysical Review B
PublisherAmerican Physical Society
- AM (Accepted Manuscript)
Rights holder© American Physical Society
Publisher statementThis paper was accepted for publication in the journal Physical Review B and the definitive published version is available at https://doi.org/10.1103/physrevb.106.054413