الملخص الإنجليزي
Magnetic skyrmions are nano-sized vortex-like spin textures and topological
solitons. First observed in 2009, they have unusual physical properties, making them
promising candidates for application in magnetic storage devices and spintronics. Many
studies have confirmed the existence of skyrmions in a wide variety of magnetic materials
including thin films and bulk crystals. These topological spin textures can be created and
investigated by using different parameters including electric current, spin waves,
temperature, electric field, and magnetic field. However, the study of the effect of the
confined structure of thin films on the formation and stability of skyrmions in (Pt/Co/W)
multilayers of thin films has been lacking. The confinement can be used as microwires in
applications and understanding fundamental physics. In this study, our purpose is to
investigate the influence of confined structures on the creation of skyrmions under the
same magnetic field and explore other topological magnetic textures that are formed in
the sample.
In this work, (Pt/Co/W) multilayers with confined structures of the same length and
different widths have been investigated. The investigation was performed at a particular
magnetic field by magnetic force microscopy. The MFM results reveal a remarkable effect
of the confined geometry on the generation of skyrmions. The skyrmions formation has
been observed for 5 µm micro-track while the coexistence of magnetic domains,
skyrmions, antiskyrmions, and skyrmioniums has been found in 10, 25, 50, 100, and, 200
µm micro-tracks. Our MFM images demonstrate that the skyrmioniums can be generated
by the overlapping of skyrmion-antiskyrmion pairs. This observation was supported by
micromagnetic simulation performed in another study. However, skyrmioniums have not
been found in the 5 µm micro-track which suggests that the skyrmioniums degenerate
because of the confinement.
