Detecção elétrica de correntes de spin em sistemas nano-estruturados

Abstract

Spintronics is an emergent research field that seeks a better understanding of the role of electronic spin in solid state physics. Exploring electrons’ charge and spin, significant technological advances might be achieved, enabling the development of revolutionary devices. Generation, manipulation and detection of spin currents are key aspects for spintronics. By exciting the ferromagnetic resonance (FMR), it is possible to generate pure spin currents through spin pumping effect. These currents propagate from a ferromagnetic layer into an adjacent non-magnetic metallic (NM) layer. In the NM material, spin orbit coupling gives rise to spin dependent scattering, converting spin currents in charge currents that may be easily detected. This phenomenon is known as inverse spin Hall effect (ISHE). The main goal of the present work is to study ISHE in nanostructured films growth by magnetron sputtering. To establish FMR, we will use a shorted microstripline connected to a vector network analyzer. Electrical dc signals will be measured with a nanovoltmeter directly connected to the films. Since different mechanism may generate a dc voltage across samples in FMR, two methods will be employed to properly separate their contributions. The first one is based on an angular measurement, the second on the inversion of the spin current injection direction.