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

TL;DR

This paper introduces a new transfer process for monocrystalline YIG microstructures onto various substrates, maintaining excellent magnetic properties, enabling advanced spin dynamics experiments and device integration.

Contribution

A novel transfer technique for YIG microstructures onto arbitrary substrates that preserves magnetic quality and broadens experimental and device applications.

Findings

YIG structures retain low Gilbert damping after transfer.

Ferromagnetic resonance linewidth of approximately 195 μT at room temperature.

Successful magnon spectrum measurement on micron-sized YIG at 5 K.

Abstract

We present a novel 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 $\mu_0\Delta H_{HWHM}\approx 195\,\mu T$ and we were even able to inductively measure magnon spectra on a single micron-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 new types of spin dynamics experiments up to now unthinkable.