Dresden 2014 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 55: Poster II
MA 55.42: Poster
Freitag, 4. April 2014, 10:30–13:30, P2
DC-Inverse Spin Hall Effect in Permalloy/Normal Metal Bilayers — •Martin Obstbaum1, Markus Härtinger1, Hans G. Bauer1, Thomas Meier1, Fabian Swientek1, Christian H. Back1, and Georg Woltersdorf1,2 — 1Institut für Experimentelle und Angewandte Physik, Universität Regensburg,93040 Regensburg, Germany — 2Physik, Martin Luther-Universität Halle, von Danckelmann-Platz 3, 06120 Halle
We present a study of the dc-voltage generation by the inverse spin Hall effect (ISHE) and the anisotropic magnetoresistance (AMR) in permalloy/normal metal bilayers at ferromagnetic resonance (FMR). We use a coplanar waveguide (CPW) structure implementing different excitation geometries. At FMR spin currents with a small dc-component are injected into the normal metal layer due to the spin pumping effect. Measurements of permalloy/platinum and permalloy/gold show that the ISHE and the AMR effect can only be separated for certain conditions. Furthermore, we point out that a conductive layer (e.g. Pt, Au) attached to the permalloy layer generates a significant additional Oersted field in experiments using a CPW. Our study provides a robust experimental basis in the quest for materials showing a large spin Hall angle. We present a reliable determination of spin Hall angles for platinum and gold and a study of ISHE in tantalum, tungsten and metal alloys such as copper-bismuth. Moreover, the contributions to voltages measured at FMR have been studied as a function of temperature and the results are compared to theoretical models.