Berlin 2018 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

MA: Fachverband Magnetismus

MA 52: Poster II

MA 52.12: Poster

Donnerstag, 15. März 2018, 15:00–18:00, Poster C

Magnetic Damping of normal metal/CoFe heterostructures — •Luis Flacke, Mathias Weiler, Matthias Althammer, Stephan Geprägs, and Rudolf Gross — Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany

The generation of high frequency from a dc-current is an important aspect in microwave technology. Such a generation can be achieved by driving auto-oscillations in a ferromagnet (FM) using a pure spin current generated by the spin Hall effect in an adjacent normal metal (NM) by a dc charge current drive. The required electrical current densities J to achieve auto-oscillations are still of the order of 10⁷ A cm⁻² [1]. A possible pathway to reduce J is to use materials with low intrinsic magnetic damping. To this end, we fabricated NM/FM/NM heterostructures by DC-sputtering using Co₂₅Fe₇₅ as the FM and Ta, Pt, Al as the NM and varying their respective deposition parameters and thicknesses. The magnetic properties of these multilayers were then investigated by broadband ferromagnetic resonance spectroscopy at room temperature. From these measurements we extracted the Gilbert damping parameter for all investigated multilayers. We discuss the obtained damping parameters with respect to contributions originating from spin pumping and intrinsic effects. Moreover, we show how our results can be employed to optimize auto-oscillations in such multilayerstructures based on the Co₂₅Fe₇₅ alloys.

[1] C. Stamm et al., Phys. Rev. Lett. 119, 087203 (2017)

*Financial support via the Nanosystems Initiative Munich is gratefully acknowledged.