We experimentally demonstrate tight focusing of a spin wave beam excited in extended nanometer-thick films of yttrium iron garnet by a simple microscopic antenna functioning as a single-slit near-field lens. We show that the focal distance and the minimum transverse width of the focal spot can be controlled in a broad range by varying the frequency/wavelength of spin waves and the antenna geometry. The experimental data are in good agreement with the results of numerical simulations. Our findings provide a simple solution for the implementation of magnonic nanodevices requiring a local concentration of the spin-wave energy.
Sub-micrometer near-field focusing of spin waves in ultrathin YIG films
B. Divinskiy, N. Thiery, L. Vila, O. Klein, N. Beaulieu, J. Ben Youssef, S. O. Demokritov, V. E. Demidov; Sub-micrometer near-field focusing of spin waves in ultrathin YIG films. Appl. Phys. Lett. 10 February 2020; 116 (6): 062401. https://doi.org/10.1063/1.5131689
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