Backward volume vs Damon-Eshbach: A traveling spin wave spectroscopy comparison

We compare the characteristics of electrically transduced Damon-Eshbach spin-wave (DESW) and backward volume spin-wave (BVSW) configurations within the same, 30 nm thick, ferromagnetic, CoFeB waveguide. Sub-micrometer U-shaped antennas are used to deliver the necessary in-plane and out-of-plane RF fields. We measure the spin-wave transmission with respect to in-plane field orientation, frequency, and propagation distance. Unlike DESW, BVSWs are reciprocally transduced and collected for either direction of propagation, but their ability to transport energy is lower than DESWs for two reasons. This arises first because BVSWs are inductively transduced less efficiently than DESWs. Also, in the range of wavevectors (similar to 5 rad mu m(-1)) typically excited by our antennas, the group velocity of BVSWs stays lower than that of DESW, which leads to reduced propagation ability that impact transmission signals in an exponential manner. In contrast, the group velocity of DESWs is maximum at low fields and decreases continuously with the applied field. The essential features of the measured SW characteristics are well reciprocated by a simple, 1D analytical model, which can be used to assess the potential of each configuration. Published under license by AIP Publishing.