CIDWM-NANOSTRIPS · Current-induced domain wall motion in magnetic nanostrips

The recent progress in the fabrication and direct synthesis of laterally confined structures, thanks to lithography techniques, has given rise to renewed interest in understanding the interaction between spin-polarized current and magnetic domain walls (DWs), because of it is a key technology for the future spintronics. Although there are several possible ways in which current can interact with magnetic domains, the most interesting interaction is that in which spin angular momentum transferred from the spin-polarized current results in motion of the domain wall. The main aim of the present project is the study of CIDWM in nanostrips with different configurations of magnetic anisotropy. As a starting point, permalloy nanostrips with longitudinal anisotropy will be analyzed, where the composition will be varied in order to modify the STT. In a second stage, the project will be focused towards more original systems with perpendicular anisotropy. The research combines different activities: elaboration and nanofabrication of metallic nanostrips, study of the domain wall motion induced by spin-polarized current (this includes analysis of DW topology, depinning, velocity, mobility and position as a function of dimensions of nanostrips and current) using advanced magnetic imaging techniques, and advances in the micromagnetic modeling of the spin transfer torque. An important aspect of this project will be the effort for understanding inconsistencies and unresolved issues in the interaction of spin-polarized current with DW (existence and nature of non adiabatic contribution, thermal effects, maximum speed of DW driven by current and magnitude of current required to sustain the motion of DW along a nanostrip), whose answer will determine how useful CIDWM will be for technological applications. Therefore, the project pretends to include a good balance between fundamental, applied and theoretical research