Dresden 2011 – wissenschaftliches Programm

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KR: Fachgruppe Kristallographie

KR 5: Poster Multiferroics (Joint Session of MA, DF, DS, KR, TT)

KR 5.86: Poster

Dienstag, 15. März 2011, 10:45–13:00, P2

Linear and nonlinear collective modes in coupled-discs magnetic microstructures — •Henning Ulrichs¹, Vladislav E. Demidov¹, Alexey V. Ognev², Maxim E. Stebliy², Ludmila A. Chebotkevich², Alexander S. Samardak², and Sergej O. Demokritov¹ — ¹Institut für angewandte Physik, Universität Münster, Corrensttraße 2-4, 48149 Münster, Germany — ²Laboratory of Thin Film Technologies, Far Eastern National University, Sukhanova street 8, 690950 Vladivostok, Russia

We have studied experimentally collective spin-wave modes in microscopic magnetic structures constituted by three coupled Permalloy discs, magnetized in-plane. By using phase-sensitive Brillouin light scattering spectroscopy we were able to clearly identify and investigate different types of the collective modes. In particular, we show that the studied systems support two fundamental modes characterized by in-phase and out-of-phase magnetization oscillations in neighboring discs. The in-phase mode demonstrates a maximum amplitude for the disc located in the center of the structure. Increasing the power of the excitation signal, the difference in the amplitudes in the neighboring discs tends to disappear. This behavior can be understood by assuming a nonlinear generation of higher-order spatial spin-wave harmonics. We will also discuss the role of magnetic bridges connecting individual discs. Our results show that the main characteristics of the modes are practically independent of the static field and the geometry of bridges, but are significantly affected by the nonlinearity.