Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 21: Poster I
MA 21.44: Poster
Dienstag, 13. März 2018, 09:30–13:00, Poster A
Terahertz Spin Currents and Spin Hall Effect in β-Tungsten and AuxPt1−x Alloys — •Oliver Gueckstock1, Mohammadreza Rouzegar1, Tom Seifert1, Sebastian Dapper2, Satya Prakash Bommanaboyena2, Björn Gliniors2, Lukas Liensberger3, Martin Wolf1, Mathias Weiler3, Markus Meinert2, and Tobias Kampfrath1,4 — 1FHI der MPG, Berlin — 2U Bielefeld, Bielefeld — 3WMI, Garching — 4FU Berlin, Berlin
The efficient conversion of spin into charge currents by spin-orbit interaction (SOI) will be important for future spin-based electronics [1]. Recently, much effort has been devoted to the identification of new large-SOI materials. One promising material is β-tungsten, for which large spin Hall angles (SHA) have been reported [2]. In our experiments, we employ femtosecond optical pulses to trigger ultrafast spin transport in magnetic thin-film stacks. Due to SOI, this spin current is partially converted into a transverse charge current which is monitored by detecting the concomitantly emitted THz electromagnetic radiation [3,4]. In particular, we study THz emission from bilayers of cobalt-iron-boron (CoFeB) and β-tungsten with varying oxygen concentration and bilayers of CoFeB and AuxPt1−x alloys. By additionally measuring the THz conductivity of these films, we can separate the influence of the spin Hall conductivity and the longitudinal conductivity to the SHA.
References: [1] S.A. Wolf et al., Science 294.5546 (2001), [2] K. Demasius et al., Nature Comm. 7, 10644 (2016), [3] T. Kampfrath et al., Nature Nanotech. 8, 256 (2013), [4] T. Seifert et al., Nature Phot. 10, 483 (2016)