We report strong amplification of the photomagnetic spin precession in Co-doped YIG employing a surface plasmon excitation in a metal-dielectric magneto-plasmonic crystal. Plasmonic enhancement is accompanied by the localization of the excitation within the 300 nm thick layer inside the transparent dielectric garnet. Experimental results are nicely reproduced by numerical simulations of the photomagnetic excitation. Our findings demonstrate the magneto-plasmonic concept of subwavelength localization and amplification of the photomagnetic excitation in dielectric YIG:Co, which can potentially be employed for all-optical magnetization switching below the diffraction limit, with energy efficiency approaching the fundamental limit for magnetic memories.
