Dresden 2009 – scientific programme

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MA: Fachverband Magnetismus

MA 2: Spin-Dynamics / Spin-Torque I

MA 2.9: Talk

Monday, March 23, 2009, 13:00–13:15, HSZ 04

New 2D approach to the k-vector sensitivity in the Brillouin light scattering spectroscopy — •Christian W. Sandweg, Vitaliy I. Vasyuchka, Alexander A. Serga, and Burkard Hillebrands — FB Physik und Forschungszentrum OPTIMAS, TU Kaiserslautern, 67663 Kaiserslautern, Germany

An important step towards the understanding of the behavior of magnon gases and condensates in thin magnetic films will potentially allow one to determine the exact spectral positions of spin-wave excitations through experimental recognition of their frequencies and wave vectors. For the investigation and characterization of energy transfer processes initiated in a magnon gas by parametric excitation, an instrument capable of detecting and resolving the whole range of magnon wave vectors occurring during these processes is required. Here we report on our progress towards achieving this goal by varying the angle of incident light with respect to the orientation of magnetization. The distinct improvement of our approach is expanding this k-vector sensitivity to two dimensions so that spin-wave wavevectors oriented both parallel and perpendicular to the external field can be resolved and measured. The functionality of this setup is demonstrated by showing the results for (a) directly excited spin waves near the ferromagnetic resonance and (b) for magnons at the lowest energy state of a parametrically driven magnon gas in yttrium-iron-garnet ferrimagnetic film.