Estudo, via simulações, do comportamento de vórtices em nanodiscos magnéticos

Abstract

In the last years, the progress of the nanotechnology allowed the production of magnetic samples with dimensions in the nanometric scale, as well as the evolution of experimental techniques to measure their properties. It was verified experimentally that the fundamental state of a Magnetic Nanodisk can be the Vortex configuration or the single domain configuration, depending on parameters as ray and thickness of Magnetic Nanodisk. In nanometric scale, the border effect and the magnetostatic energy become important, creating a border anisotropy on the close spins to the border. Theoretical forecasts indicate that the fundamental state of a Magnetic Nanodisk should be the single domain configuration. It is important to emphasize that such forecasts are based on theories that don't take into account the thickness of the border. In the subsequent text we analyzed, by Monte Carlo simulations, the effect of the thickness of the border on the establishment of the fundamental state in Magnetic Nanodisks. Our results showed that the thickness of the border possesses considerable influence on the establishment of the fundamental state in such systems. We also analyzed, by Monte Carlo simulations and Spin Dynamics, the effect of the inclusion of a circular hole, in the center of a Magnetic Nanodisk, about the Vortex configuration. In this case, our results showed that the hole pinning the Vortex configuration. Such effect might be used for switching schemes employing pinning and depinning of the Vortex configuration by holes in Magnetic Nanodisks submitted to external field.