On-chip magnon-phonon coupling in SAW-based cavity magnomechanics
ORAL · Invited
Abstract
Microscale devices based on elastic-wave phononic resonators—such as bulk acoustic resonators and surface acoustic wave (SAW) microwave filters—have been widely employed in various practical applications, including mobile communication terminals, automotive electronics, diverse sensors, and precision timing devices. Further advances in multifunctionality, integration, and high-frequency operation are essential for their continued evolution. We aim to realize novel functionalities through coupled operation between ferromagnetic materials and SAW-based phononic resonators, thereby establishing on-chip magnon–phonon hybrid devices.
One of the most important targets in this study is the hybridization of two fundamental excitations—phonons and magnons—leading to the formation of magnon polarons. A key milestone toward this goal is the realization of the strong coupling by enhancing the coupling strength and minimizing damping rates. We demonstrated the strong magnon–phonon coupling using a novel layered structure consisting of piezoelectric aluminum nitride on a ferromagnetic YIG thin film. The large spatial mode overlap between the phonon and magnon modes enables their strong coupling with a cooperativity of 25.0 ± 5.5 at 0.93 GHz [1].
Another advancement in our studies is the demonstration of magnon–phonon coupling within a phononic crystal (PnC) nanocavity. A phononic crystal is an artificial structure in which periodic modulation of the elastic modulus forms a phononic band structure. This allows acoustic phonons to be guided and confined within wavelength-scale acoustic cavities and waveguides, enabling the manipulation of magnetic elements embedded in a PnC circuit. Moreover, the cavity provides diverse spatial distributions of vibrational strain among different acoustic modes, enabling precise tailoring of magnetoelastic coupling. We have demonstrated acoustic pumping of localized ferromagnetic magnons, where the magnon back-action induces dynamic and mode-dependent modulation of the phononic cavity resonances [2].
[1] D. Hatanaka, et al., “On-chip magnon polaron generation in mode-matched cavity magnomechanics”, arXiv:2507.03577.
[2] D. Hatanaka, et al., “Phononic crystal cavity magnomechanics”, Phys. Rev. Appl. 19, 054071 (2023).
One of the most important targets in this study is the hybridization of two fundamental excitations—phonons and magnons—leading to the formation of magnon polarons. A key milestone toward this goal is the realization of the strong coupling by enhancing the coupling strength and minimizing damping rates. We demonstrated the strong magnon–phonon coupling using a novel layered structure consisting of piezoelectric aluminum nitride on a ferromagnetic YIG thin film. The large spatial mode overlap between the phonon and magnon modes enables their strong coupling with a cooperativity of 25.0 ± 5.5 at 0.93 GHz [1].
Another advancement in our studies is the demonstration of magnon–phonon coupling within a phononic crystal (PnC) nanocavity. A phononic crystal is an artificial structure in which periodic modulation of the elastic modulus forms a phononic band structure. This allows acoustic phonons to be guided and confined within wavelength-scale acoustic cavities and waveguides, enabling the manipulation of magnetic elements embedded in a PnC circuit. Moreover, the cavity provides diverse spatial distributions of vibrational strain among different acoustic modes, enabling precise tailoring of magnetoelastic coupling. We have demonstrated acoustic pumping of localized ferromagnetic magnons, where the magnon back-action induces dynamic and mode-dependent modulation of the phononic cavity resonances [2].
[1] D. Hatanaka, et al., “On-chip magnon polaron generation in mode-matched cavity magnomechanics”, arXiv:2507.03577.
[2] D. Hatanaka, et al., “Phononic crystal cavity magnomechanics”, Phys. Rev. Appl. 19, 054071 (2023).
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Publication: - D. Hatanaka, et al., "On-chip magnon polaron generation in mode-matched cavity magnomechanics", arXiv:2507.03577.
- D. Hatanaka, et al., "Phononic crystal cavity magnomechanics", Phys. Rev. Appl. 19, 054071 (2023).
Presenters
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Hiroshi Yamaguchi
- NTT Basic Research Labs