2021/07/20 by Marek Vaňatka, Krzysztof Szulc, Vaňatka, Marek +15
Physics and Astronomy · Engineering · #Magnetic properties of thin films #Magneto-Optical Properties and Applications #Physics of Superconductivity and Magnetism
paper · pdf · doi:10.48550/arxiv.2107.09363
Magnonics is seen nowadays as a candidate technology for energy-efficient\ndata processing in classical and quantum systems. Pronounced nonlinearity,\nanisotropy of dispersion relations and phase degree of freedom of spin waves\nrequire advanced methodology for probing spin waves at room as well as at mK\ntemperatures. Yet, the use of the established optical techniques like Brillouin\nlight scattering (BLS) or magneto optical Kerr effect (MOKE) at ultra-low\ntemperatures is forbiddingly complicated. By contrast, microwave spectroscopy\ncan be used at all temperatures but is usually lacking spatial and wavenumber\nresolution. Here, we develop a variable-gap propagating spin-wave spectroscopy\n(VG-PSWS) method for the deduction of the dispersion relation of spin waves in\nwide frequency and wavenumber range. The method is based on the phase-resolved\nanalysis of the spin-wave transmission between two antennas with variable\nspacing, in conjunction with theoretical data treatment. We validate the method\nfor the in-plane magnetized CoFeB and YIG thin films in k\⊥ B and\nk\∥ B geometries by deducing the full set of material and spin-wave\nparameters, including spin-wave dispersion, hybridization of the fundamental\nmode with the higher-order perpendicular standing spin-wave modes and surface\nspin pinning. The compatibility of microwaves with low temperatures makes this\napproach attractive for cryogenic magnonics at the nanoscale.\n