Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 32: Postersession II: Spinstruct./Phase Trans. (1-10); Spinelectronics (11-15); Thin Films (16 - 36); Particles/Clusters (37-45); Multiferroics (46-54); Spindynamics/Spin Torque (55 - 76); Post Deadlines (77-79)
MA 32.65: Poster
Freitag, 29. Februar 2008, 11:15–14:00, Poster E
Ferromagnetic resonance study of interlayer exchange-coupled NiFe/Ru/NiFe films. — Mohamed Belmeguenai1, •Tobias Martin1, Georg Woltersdorf1, Vincent Baltz2, Anna Suszka2, Bryan Hickey2, and Günther Bayreuther1 — 1Institut f. Exper. und Angew. Physik, Universität Regensburg, 93040 Regensburg — 2University of Leeds, Leeds, UK
Vector network analyzer ferromagnetic resonance spectroscopy (VNA-FMR) was used to study the different excited modes of sputtered symmetric [NiFe(30nm)/Ru(dRu)/NiFe(30nm)] and asymmetric [NiFe(13.6nm)/Ru(dRu)/NiFe(27.2nm)] exchange-coupled Permalloy films with variable Ru thicknesses, dRu. Always an optic and an acoustic precessional mode is observed. For the conventional geometry with dc bias field and rf field perpendicular to each other the optic mode was only observed over a limited field range. This restriction was overcome by orienting the bias and rf field parallel to each other. The variation of the mode frequencies with the dc field was directly related to the different magnetic states of the two NiFe layers. Interestingly, in asymmetric trilayers characteristic jumps were observed for the resonance field as a function of the dc bias field. This "anti-crossing" behavior is well reproduced by numerical simulations, as well as the effect of the biquadratic coupling on the mode frequency.