Estudo do comportamento da magnetização de nanoilhas magnéticas via simulação computacional

Abstract

It is important to investigate the basic properties of magnetic systems since it has many applications in logic devices, sensors, media storage high-density data and magnetic random access memory (MRAM) devices. These factors have drawn attention to many scientists in recent years devoting themselves for studying nanostructured magnetic systems. From a scientific and technological point of view, having static and dynamic control of nanostructures is fundamental for possible technological applications. In this context, in the present work, we performed a study with elongated and planar nanoparticles made of Permalloy-79, a soft ferromagnetic material that has low magnetocrystalline anisotropy. In these materials, the magnetic configuration depends on the sample geometry, due to the phenomenon known as shape anisotropy. The nanoelipses studied in this work present magnetic monodomains in the ground state, which makes them interesting for use in systems known as spin ice. This work aimed to study nanoelipses with two aspect ratios, both presenting magnetic monodomains, their thickness ranged from 5 to 20 nm. Next, we consider magnetic systems containing seven nanoelipses, whose arrangement favors the spin ice rule to be satisfied. Therefore, the energies of the configurations were analyzed upon reaching the less energetic state. We found that the spin ice setting is less energetic than the other four settings. In the sequence, it was found that the separation distances from edge to edge between the system nanoelipses, in which the effects of the dipole interaction does not interfere in the initial state of the magnetization in the nanoelipse. After determining this separation distance, the external magnetic field corresponding to each nanomagnet was applied, and then the magnetization inversion process was analyzed. All Magnetization inversion processes happen with high coherence index.