Damping enhancement in YIG at millikelvin temperatures due to GGG substrate

Damping enhancement in YIG at millikelvin temperatures due to GGG substrate

Článek recenzovaný mimo WoS a Scopus

Quantum magnonics aims to exploit the quantum mechanical properties of magnons for nanoscale quantum information technologies. Ferrimagnetic yttrium iron garnet (YIG), which offers the longest magnon lifetimes, is a key material typically grown on gadolinium gallium garnet (GGG) substrates for structural compatibility. However, the increased magnetic damping in YIG/GGG systems below 50 K poses a challenge for quantum applications. Here, we study the damping in a 97 nm-thick YIG film on a -thick GGG substrate at temperatures down to 30 mK using ferromagnetic resonance (FMR) spectroscopy. We show that the dominant physical mechanism for the observed tenfold increase in FMR linewidth at millikelvin temperatures is the non-uniform bias magnetic field generated by the partially magnetized paramagnetic GGG substrate. Numerical simulations and analytical theory show that the GGG-driven linewidth enhancement can reach up to 6.7 times. In addition, at low temperatures and frequencies above 18 GHz and temperatures below 2 K and frequencies above 10 GHz, the FMR linewidth deviates from the viscous Gilbert-damping model. These results allow the partial elimination of the damping mechanisms attributed to GGG, which is necessary for the advancement of solid-state quantum technologies.

Quantum magnonics aims to exploit the quantum mechanical properties of magnons for nanoscale quantum information technologies. Ferrimagnetic yttrium iron garnet (YIG), which offers the longest magnon lifetimes, is a key material typically grown on gadolinium gallium garnet (GGG) substrates for structural compatibility. However, the increased magnetic damping in YIG/GGG systems below 50 K poses a challenge for quantum applications. Here, we study the damping in a 97 nm-thick YIG film on a -thick GGG substrate at temperatures down to 30 mK using ferromagnetic resonance (FMR) spectroscopy. We show that the dominant physical mechanism for the observed tenfold increase in FMR linewidth at millikelvin temperatures is the non-uniform bias magnetic field generated by the partially magnetized paramagnetic GGG substrate. Numerical simulations and analytical theory show that the GGG-driven linewidth enhancement can reach up to 6.7 times. In addition, at low temperatures and frequencies above 18 GHz and temperatures below 2 K and frequencies above 10 GHz, the FMR linewidth deviates from the viscous Gilbert-damping model. These results allow the partial elimination of the damping mechanisms attributed to GGG, which is necessary for the advancement of solid-state quantum technologies.

FMR at millikelvin temperatures; Quantum magnonics; Yttrium iron garnet; Ferrimagnet/paramagnet bilayer; Magnetic damping

FMR at millikelvin temperatures; Quantum magnonics; Yttrium iron garnet; Ferrimagnet/paramagnet bilayer; Magnetic damping

SERHA, R.; VORONOV, A.; SCHMOLL, D.; KLINGBEIL, R.; KNAUER, S.; KORALTAN, S.; PRIBYTOVA, E.; LINDNER, M.; REIMANN, T.; DUBS, C.; CLAAS, A.; VERBA, R.; URBÁNEK, M.; SUESS, D.; CHUMAK, A.

2026

01.03.2025

Elsevier

Materials Today Quantum

5

3

Nizozemsko

100025

10025

9

https://www.sciencedirect.com/science/article/pii/S2950257825000034

http://hdl.handle.net/11012/255629