Dresden 2011 – scientific programme

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MA: Fachverband Magnetismus

MA 31: Magnetization Dynamics III

MA 31.7: Talk

Wednesday, March 16, 2011, 12:30–12:45, HSZ 403

Nonlinear hybridization of the fundamental eigenmodes of microscopic ferromagnetic ellipses — •Matthias Buchmeier¹, Vladislav E. Demidov¹, Karsten Rott², Patryk Krzysteczko², Jana Münchenberger², Günter Reiss², and Sergej O. Demokritov¹ — ¹Institute for Applied Physics, University of Münster, Germany — ²Department of Physics, Bielefeld University, Germany

We present an experimental study of nonlinear eigenmodes of microscopic Permalloy elliptical elements using micro-focus Brillouin light scattering spectroscopy, a technique providing sub-micrometer spatial resolution. We find that two fundamental eigenmodes of such ferromagnetic elements, the edge and the center mode, show an essentially different nonlinear behavior [1]. With increasing amplitude, the frequency of the edge mode exhibits a continuous positive nonlinear shift. On the other hand the frequency of the center mode stays unchanged until it is approached by the edge mode. Subsequently the modes hybridize which influences both the frequencies and the spatial distributions of the dynamic magnetization. As a consequence of this nonlinear hybridization the distributions lose the shape well known for the linear regime and take a hybrid form. Our findings contribute to the deep understanding of the essentially nonlinear large-amplitude magnetization dynamics in microscopic magnetic-film structures, which is of special importance for the understanding of spin-transfer-torque and microwave-assisted magnetization-switching phenomena.
V. E. Demidov et al., Phys. Rev. Lett. 104, 217203 (2010).