Spin Transfer from a Ferromagnet into a Semiconductor through an Oxide barrier

We present results on the magnetoresistance of the system Ni/Al203/n-doped Si/Al2O3/Ni in fabricated nanostructures. The results at temperature of 14K reveal a 75% magnetoresistance that decreases in value up to approximately 30K where the effect disappears. We observe minimum resistance in the antiparallel configurations of the source and drain of Ni. As a possibility, it seems to indicate the existence of a magnetic state at the Si/oxide interface. The average spin diffusion length obtained is of 650 nm approximately. Results are compared to the window of resistances that seems to exist between the tunnel barrier resistance and two threshold resistances but the spin transfer seems to work in the range and outside the two thresholds

Controlling domain wall oscillations in bent cylindrical magnetic wires

[EN] Magnetic cylindrical nanowires are promising candidates for future three-dimensional nanotechnology. Domain walls (DWs) in magnetic nanowires play the role of information carriers, and the development of applications requires proper description of their dynamics. Here we perform a detailed analytical and numerical analysis of the DW motion along a bent magnetic nanowire under the action of tangential magnetic fields. Our results show that the DW velocity, precession, and oscillation frequencies can be controlled by the interplay between the curvature and the external magnetic field. Small magnetic fields induce a DW motion without precession and oscillatory behavior, while higher magnetic fields yield a Walker breakdown regime, in which an oscillatory forward and backward DW motion is observed. Controlled DW motion under the Walker breakdown regime makes magnetic nanowires potential candidates for nanoscale microwave generation and sensing.In Brazil, this study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior -Brasil (CAPES) - Finance Code 001. The authors also thank CNPq (Grants No. 401132/2016-1 and No. 302084/2019-3). In Scotland, we acknowledge the Natural Environment Research Council (Grant No. NE/S011978/1). In Chile, we acknowledge financial support from FONDECYT Grant No. 1160198 and CONICYT through Centro Basal FB0807. In Spain, we acknowledge the financial support from the Ministry of Economy and Competitivity under Grant No.MAT2016-76824-C3-1-R