%0 Thesis
%A Aldarawsheh, Amal
%T Ab initio investigation of intrinsic antiferromagnetic solitons
%V 286
%I Duisburg-Essen University
%V Dissertation
%C Jülich
%M FZJ-2024-06127
%@ 978-3-95806-785-1
%B Reihe Schlüsseltechnologien / Key Technologies
%P xv, 164
%D 2024
%Z Dissertation, Duisburg-Essen University, 2024
%X The field of spintronics is poised to transform technology with faster, more efficient, and energy-saving devices by exploring magnetic nanostructures for miniaturization. This thesis uses a multi-scale modeling approach, combining density functional theory and atomistic spin dynamics to study topological antiferromagnetic (AFM) spin-swirling textures in thin films. These textures are seen as ideal dynamic bits for information transmission and storage, offering advantages over ferromagnetic (FM) solitons. While progress has been made in synthetic AFM multilayers, the observation of intrinsic AFM solitons within film geometry remains elusive. The thesis predicts a realistic combination of ultrathin films capable of hosting a variety of intrinsic topological AFM solitons with unique properties, exploring their emergence mechanisms, stability, response to stimuli, and dynamics. In our study, we choose transition metal layers that are expected to be AFM such as Cr and Mn, interfaced with Ir(111) surface, to investigate the formation of AFM solitons. We predict the emergence of intrinsic single and, surprisingly, interchained AFM skyrmions in the rowwise AFM (RW-AFM) ground state of a Cr layer on PdFe/Ir(111) surface. The stabilization mechanisms involve Heisenberg exchange interactions, Dzyaloshinskii-Moriya interactions, and magnetocrystalline anisotropy. The energy barriers and the overlap of AFM skyrmions are also explained. Then, we take a step further by developing a generic atomistic spin model with the minimum magnetic interactions required to stabilize those AFM skyrmions. This model enhances the understanding of the complex phase behavior of AFM skyrmions, showing their sensitivity to diverse magnetic interactions and external magnetic fields. When Cris replaced with a Mn layer, a new type of AFM solitons, frustrated multi-meronic textures such as hexa-merons and tri-merons, are observed in different configurations of Mn based systems. We delve into the mechanisms underlying their emergence, investigate their properties and how different topological charges influence their response to external magnetic fields. The study also explores the dynamics of AFM skyrmions under the influence of a spinpolarized current-perpendicular-to-plane. Anisotropic skyrmion Hall effect is observed, resulting from the elliptical shape of these AFM skyrmions. Additionally, the interaction between FM and AFM skyrmions influences the trajectories of AFM skyrmions, creating a complex hybrid interaction profile. Finally, we propose a bottom-up approach for the construction of topological magnetic textures in diluted structures made of Cr, Mn or Fe adatoms on Nb(110) surface and demonstrate the manifestation of a rich set of topological spin-textures of FM and AFM nature.
%F PUB:(DE-HGF)3 ; PUB:(DE-HGF)11
%9 BookDissertation / PhD Thesis
%R 10.34734/FZJ-2024-06127
%U https://juser.fz-juelich.de/record/1032288