Weakly pinned skyrmion liquid in a magnetic heterostructure

Loading...
Thumbnail Image
Access rights
openAccess
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2022-08-10
Major/Subject
Mcode
Degree programme
Language
en
Pages
11
1-11
Series
Physical Review B, Volume 106, issue 5
Abstract
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.
Description
Funding Information: This work was supported by the Academy of Finland (Grants No. 295269, No. 306978, and No. 327804). K.R.E. acknowledges funding from the NSF (Grant No. NSF-MPS-2006456). E.G. was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo -FAPESP (Grant No. 18/19586-9). T.A.-N. has been supported in part by the Academy of Finland QTF CoE Grant No. 312298. Publisher Copyright: © 2022 American Physical Society.
Keywords
Other note
Citation
Mansell , R , Zhou , Y , Kohvakka , K , Ying , S C , Elder , K R , Granato , E , Ala-Nissila , T & Van Dijken , S 2022 , ' Weakly pinned skyrmion liquid in a magnetic heterostructure ' , Physical Review B , vol. 106 , no. 5 , 054413 , pp. 1-11 . https://doi.org/10.1103/PhysRevB.106.054413