Control of magnetic textures interacting with defects aiming applications in spintronics

Abstract

The constant search for the miniaturization of electronic components has been one of the biggest challenges for application in new processors and logic devices. However, the spintronics proposal, in which the electron's spin is essential rather than the charge, demonstrates remarkable effectiveness with low energy consumption and stability. This makes spintronics one of the main promises for the future of conventional electronics, especially when considering the new emerging topological spin structures. These structures, also called magnetic textures, have emerged as promising alternatives for processing information in nanometer-scale devices. Among the best-known magnetic textures we can mention skyrmions, merons, bi-merons and skyrmioniums. Magnetic skyrmions are non-trivial spin structures that have been widely studied in recent years due to their topological protection and because they have low transport currents, through the application of polarized spin current. Merons are topologically equivalent to a half-skyrmion, which exist only in pairs or groups in ferromagnetic films. However, a bimeron can be stabilized individually in a ferromagnetic film. Finally, skyrmionium is a ring-shaped spin texture that can be understood as a skyrmion within another skyrmion. These spin textures can be individualized through their topological charge, and have distinct stabilization and dynamic characteristics, which are still under constant study. Precise control of the movement of these textures is essential for device applications. Using computational simulations based on the atomistic model, we aim to simulate the stabilization and dynamic behavior of skyrmions, bimerons and skyrmioniums in ferromagnetic thin films in the presence of defects. We will study dynamic behaviors of skyrmions in the presence of linear protrusions-type obstacles on a racetrack, with the aim of proposing devices based on skyrmions. We will also investigate the dynamic behavior of skyrmions when transported by heterogeneous films with materials of different magnetic properties interspersed. Regarding bimerons and skyrmioniums, we will focus on the conditions of static and dynamic stability when transported through interfaces between different materials with different magnetic properties. After establishing the stabilization conditions, we will apply a transport current to induce the movement of the textures across the interface, aiming to identify the conditions for the beginning of the movement, dynamic regimes and possible topological transitions or annihilations. We hope that these results will contribute to a better understanding of the dynamics of these structures and open new possibilities for spintronics devices. (AU)