Dresden 2017 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 48: Spin Dynamics and Transport: Spin Excitations and Spin Torque Phenomena
MA 48.10: Vortrag
Donnerstag, 23. März 2017, 12:00–12:15, HSZ 101
Spin Hall magnetoresistance up to the THz regime: Signal magnification with spin-waves excitations — •Filipe Souza Mendes Guimarães1, Manuel dos Santos Dias1, Juba Bouaziz1, Antonio Tavares da Costa2, Roberto Bechara Muniz2, and Samir Lounis1 — 1Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany — 2Universidade Federal Fluminense, Niterói, Brazil
Spin-orbit-related effects offer the utmost standard of reading and writing information in magnetic units for future devices. These phenomena rely not only on the static orientation of the magnetization but also on its dynamics to achieve fast switchings that can reach the Terahertz regime.[1] In this work, we demonstrate that dynamical charge and spin pumping mechanisms can greatly magnify or dwindle the currents flowing through the system, influencing all kinds of magnetoresistive effects and also Hall currents. In contrast to the static counter-parts, the dynamical signals can be modified by a few to hundreds percents, which leads to immediate implications for device concepts in the THz range. We show, in Co/Pt and Fe/W bilayers, that the variation on the amplitude of these ac-currents can reach up to two orders of magnitude and also affect dc and second harmonic signals. We further show that, by exploring the resonance of the system, dynamical spin Hall angles can non-trivially change sign and be significantly boosted by over 1000%, reaching giant values that are comparable to the dc ones obtained in high resistivity phase of Ta and W.
[1] F. S. M. Guimarães et al., Phys. Rev. B 92, 220410(R) (2015).