Integration and characterization of micron-sized YIG structures with very low Gilbert damping on arbitrary substrates

Abstract

We present a process that allows the transfer of monocrystalline yttrium-iron-garnet microstructures onto virtually any kind of substrate. The process is based on a recently developed method that allows the fabrication of freestanding monocrystalline YIG bridges on gadolinium-gallium-garnet. Here, the bridges' spans are detached from the substrate by a dry etching process and immersed in a watery solution. Using drop-casting, the immersed YIG platelets can be transferred onto the substrate of choice, where the structures finally can be reattached and, thus, be integrated into complex devices or experimental geometries. Using time-resolved scanning Kerr microscopy and inductively measured ferromagnetic resonance, we can demonstrate that the structures retain their excellent magnetic quality. At room temperature, we find a ferromagnetic resonance linewidth of μ 0 Δ H HWHM ≈ 195 μ T and we were even able to inductively measure magnon spectra on a single micrometer-sized yttrium-iron-garnet platelet at a temperature of 5 K. The process is flexible in terms of substrate material and shape of the structure. In the future, this approach will allow for types of spin dynamics experiments until now unthinkable.