Efeito Nernst anômalo em filmes magnetostrictivos sobre substratos flexíveis

Abstract

The anomalous Nernst effect (ANE) in nanostructured magnetic materials is a crucial phenomenon for optimizing control and using internal energy in electronic devices. In this work, we will explore the magnetic properties and ANE in a flexible magnetostrictive film with uniaxial anisotropy induced and subjected to mechanical stress. In addition, we will promote integration between the ANE effect and the magnetostrictive phenomena, which influence the effective anisotropy of films. Therefore, a theoretical study of the behavior of magnetization in this system will be presented to understand how it will affect the thermoelectric voltage response. At the same time, we will integrate this study with the experimental data obtained. In this way, we can manipulate the ANE through the magnetic field and the applied mechanical stress. Theoretically, we calculate the magnetization behavior and the thermoelectric voltage response from the theoretical approach to planar geometry, with a magnetic-free energy density that takes into account the induced contributions of uniaxial and magnetoelastic anisotropy. Experimentally, we verified changes in the effective magnetic anisotropy, changing the applied stress, and explored the anomalous Nernst effect as a powerful tool to investigate the magnetic properties of magnetostrictive materials. We found agreement between the experiment and the numerical calculations, thus elucidating the magnetic behavior and the thermoelectric voltage response. Finally, an evidence was provided to confirrm the validity of the theoretical approach to describe the magnetic properties and the anomalous Nernst effect in ferromagnetic magnetostrictive films with uniaxial magnetic anisotropy and subjected to external stresses.