Magnonics Based on Thin-Film Iron Garnets

Spin waves and their quanta magnons are collective excitation of electron spins in magnetic materials which can serve as information carriers for future low-power-consumption computing systems. Ferrimagnetic thin-film iron garnets are considered as an ideal platform for spin waves due to the low Gilbert damping. Here, we review the recent progress of magnonics based on thin-film iron garnets, including the yttrium iron garnet (YIG). Short-wavelength spin waves with dispersion relation governed by the exchange interaction have recently been reported in low damping YIG thin films. Periodical nanostructure thin-film iron garnets enrich the functionalities of magnonic crystals. In addition, pure spin currents in adjacent heavy metal layers could induce magnetic auto-oscillations and propagating spin waves in thin-film iron garnets. The broken inversion symmetry has also been found in thin-film iron garnets probed by chiral spin-wave group velocities. We conclude that thin-film iron garnets hold a bright future for magnon based logic devices and circuits.