Suchergebnisse

[EN] The current-driven skyrmion (Sk) motion along two exchange-coupled ferromagnetic (FM) layers with perpendicular magnetic anisotropy is studied by means of micromagnetic simulations and compared to the conventional case of a single FM layer. Our results indicate that the two coupled Sks can be synchronously driven along each FM layer in the presence of a strong interlayer exchange coupling and that the velocity is significantly enhanced due to the antiferromagnetic (AF) exchange coupling as compared with the single-FM-layer case. The interfacial Dzyaloshinskii–Moriya interaction gives the required chirality to the magnetization textures, while the interlayer exchange coupling favors the synchronous movement of the coupled Sks by a dragging mechanism, without depicting the unwanted Sk Hall effect. This observation is particularly relevant to drive Sks along curved strips, which are also evaluated here. Sks move with different velocities along single FM stacks with curved parts. On the contrary, the AF coupling between the FM layers mitigates the Sk Hall effect, which suggests these systems to achieve efficient and highly packed displacement of trains of Sks for spintronics devices. A study taking into account defects and thermal fluctuations analyzes the validity range of these claims. ; Spanish Governmentunder Project MAT2014-52477-C5-4-P, Project MAT2017- 87072-C4-1-P, and Project MAT2017-90771-REDT Junta de Castilla y Leon under Project SA090U16 and Project SA299P18.

[EN] Micromagnetic simulations are used to investigate the motion of magnetic skyrmions in an in-plane strain gradient. The skyrmion diameter and energy are found to depend on the strain, which leads to a force that moves the skyrmion toward regions with higher strain. An analytical expression for the skyrmion velocity as a function of the strain gradient is derived assuming a rigid profile for the skyrmion, and good agreement with simulations is obtained. Furthermore, electromechanical simulations of a hybrid ferromagnetic/piezoelectric device show that the in-plane strain gradients needed to move skyrmions can be achieved ; Project No. MAT2017-87072-C4-1-P from the (Ministerio de Economía y Competitividad) Spanish government Project No. SA299P18 from Consejería de Educacíon Junta de Castilla y León.