Spin waves are of great interest as an emerging solution for computing beyond the limitations of scaled transistor technology. In such applications, the frequency of the spin waves is important as it affects the overall frequency performance of the resulting devices. In conventional ferromagnetic thin films, the magnetization dynamics in ferromagnetic resonance (FMR) and spin-waves are limited by the saturation magnetization of the ferromagnetic (FM) material and the external bias field. High-frequency applications would require high external magnetic fields which limit the practicality in a realistic device. One solution is to couple microwave excitations to perpendicular standing spin-waves (PSSWs) which can enable higher oscillation frequencies. However, efficient coupling to these modes remains a challenge since it requires an excitation that is non-uniform across the FM material thickness and current methods have proven to be inefficient, resulting in weak excitations. Here, we show that by creating periodic undulations in a 100 nm thick Co 40 Fe 40 B 20 layer, high-frequency PSSWs (>20 GHz) can be efficiently excited using micrometer sized transducers at bias fields below 100 Oe which absorb nearly 10% of the input RF power. Efficient excitation of such spin-waves at low fields may enable high

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