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MA: Fachverband Magnetismus

MA 16: Spin Dynamics: Magnetic relaxation and Gilbert Damping

MA 16.1: Vortrag

Montag, 20. März 2017, 17:30–17:45, HSZ 401

Room Temperature Spin Pumping into Cobalt Doped Zinc Oxide Evidenced by Multifrequency FMR — •Martin Buchner, Taddäus Schaffers, Bastian Henne, Verena Ney, and Andreas Ney — Johannes Kepler Universität, Linz, Austria

A precessing magnetization in a ferromagnet returns to its equilibrium position due to Gilbert damping. This damping can be increased by spin pumping, an angular momentum transfer to an adjacent non ferromagnetic layer [1]. By performing ferromagnetic resonance (FMR) measurements increased damping will result in a broadening of the linewidth. In classical, resonator-based FMR setups there is no possibility to distinguish between increased damping due to spin pumping and inhomogeneous broadening effects. This can only be achieved when measuring a frequency dependent linewidth. In this contribution we use a setup which replaces the resonator by a coaxial cable that is short-circuited at the sample side [2]. The magnetic field is induced into the sample via a microwave near field affect. In a two layer system consisting of permalloy and highly Co doped ZnO [3] film, both resonance position and the linewidth of the FMR lines, change. In the measured frequency range a 75 % increased damping parameter is found.

[1] Y. Tserkovnyak et al. Phys. Rev. Lett. 88, 117601 (2002).

[2] F. M. Römer et al. Appl. Phys. Lett. 100, 092402 (2012).

[3] B. Henne et al. Sci. Rep. 5, 16863 (2015).