Phonon -Magnon interactions in CoFeB/Au multilayers

Seminarium wydziałowe (online)

Dnia 2021-05-18 o godzinie 14:15 odbędzie się wykład (seminarium odbędzie się „online” z wykorzystaniem platformy ZOOM), na którym mgr Nandan K. P. Babu z Wydziału Fizyki Uniwersytetu im. Adama Mickiewicza w Poznaniu wygłosi wykład pt:

“Phonon -Magnon interactions in CoFeB/Au multilayers"

Serdecznie zapraszamy

Andrzej Maziewski

Nandan K. P. Babu
Wydział Fizyki Uniwersytetu im. Adama Mickiewicza w Poznaniu
“Phonon -Magnon interactions in CoFeB/Au multilayers"

Light opens up new ways of gathering information about the physical properties of matter based on the light-matter interaction, which known as spectroscopic techniques. Brillouin light scattering technique (BLS) is a well-established spectroscopic technique that measures inelastically scattered light from acoustic phonons or magnons.. This seminar focuses on the experimental observation of phonon-magnon interactions in magnetic multilayers samples using the Brillouin light scattering spectroscopy (BLS) and explaining the factors influencing the interactions with analytical calculations. The criterion for the phase and frequency matching of the elastic wave and spin wave must be fulfilled to observe such interactions. For this purpose, a CoFeB/Au multilayer with tailored magnetic and elastic properties have been studied. The BLS system is used to measure dispersion relations of thermal magnons and phonons in the multilayer of CoFeB/Au structure. The reduced spin wave frequencies in the designed multilayer allow detecting the (anti)crossing of spin wave dispersion branches with the dispersion branches of surface acoustic waves characterized natively by lower frequencies. Such anticrossing is the evidence of the interaction between spin and elastic modes, and its width depends on the interaction strength. The anisotropy of interaction (arises from the orientation of the external magnetic field) studied using in two geometries, an oblique geometry (where the angle between magnetic field and wave vector is 450) and backward volume geometry (where magnetic field and wave vector are perpendicular to each other).

Reference
1. Nandan K. P. Babu, Aleksandra Trzaskowska, Piotr Graczyk, Grzegorz Centała, Szymon Mieszczak, Hubert Głowiński, Miłosz Zdunek, Sławomir Mielcarek, and Jarosław W. Kłos(2021), “The Interaction between Surface Acoustic Waves and Spin Waves: The Role of Anisotropy and Spatial Profiles of the Modes” Nano Letters 2021 21 (2), 946-951
2. Nandan K. P. Babu, Aleksandra Trzaskowska , Slawomir Mielcarek1, Hubert Głowinski, Oleksandr M. Chumak, Milosz Zdunek, Jaroslaw W. Kłos , and Maciej Krawczyk (2019), “Interaction Between Thermal Magnons and Phonons in a CoFeB/Au Multilayer” IEEE Magnetics Letters, Volume 10 (2019).