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MA: Fachverband Magnetismus
MA 30: Spin-Torque Phenomena
MA 30.8: Talk
Wednesday, March 9, 2016, 12:00–12:15, H33
Radiative damping in waveguide-based ferromagnetic resonance measured via analysis of perpendicular standing spin waves in sputtered permalloy films — Martin Schoen1,2, Justin Shaw1, Hans Nembach1, •Mathias Weiler3, and T.J. Silva1 — 1Quantum Electromagnetics Division, National Institute of Standards and Technology, USA — 2Institute of Experimental and Applied Physics, University of Regensburg, Germany — 3Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, D-85748 Garching, Germany
In ferromagnetic resonance measurements one often neglected contribution to the measured damping is the damping enhancement due to inductive coupling between the precessing magnetization and the waveguide, the radiative damping. We investigate the radiative damping by measuring perpendicular standing spin waves in uniform 75 nm, 120 nm, and 200 nm Ni(80)Fe(20) films with multiple cap and seed layer configurations and compare the measured radiative damping to the one calculated in a simple model. The measurement of spin waves allows us to observe a direct proportionality of the damping enhancement to the spin wave inductance, as predicted by our model. Furthermore we present a method to directly measure radiative damping by decreasing the inductive coupling between sample and wave guide. Though inherently small for thin films (0.0003 for a 10 nm Permalloy film) the radiative damping can be a significant contribution to the total damping in materials with small intrinsic damping or large saturation magnetization, like yttrium-iron-garnett or Co(25)Fe(75).