Strongly coupled magnon–phonon dynamics in a single nanomagnet

Abstract

Polaritons are widely investigated quasiparticles with fundamental and technological significance due to their unique properties. They have been studied most extensively in semiconductors when photons interact with various elementary excitations. However, other strongly coupled excitations demonstrate similar dynamics. Specifically, when magnon and phonon modes are coupled, a hybridized magnon–phonon quasiparticle can form. Here, we report on the direct observation of coupled magnon–phonon dynamics within a single thin nickel nanomagnet. We develop an analytic description to model the dynamics in two dimensions, enabling us to isolate the parameters influencing the frequency splitting. Furthermore, we demonstrate tuning of the magnon–phonon interaction into the strong coupling regime via the orientation of the applied magnetic field.

Evidence for a spin acoustic surface plasmon from inelastic atom scattering

“…The dynamical properties of solids in the low-energy range (0–100 meV) are dominated by lattice vibrations (phonons). The interaction of phonons with the elementary excitations of the electronic degrees of freedom falling in the same energy range, such as Fermi-level electron-hole transitions in metals 1 , magnons in magnetic materials 2 , 3 and excitons 4 in narrow-gap semiconductors, is a very active research area in solid state physics.…”

Unidirectional Pumping of Phonons by Magnetization Dynamics

“…Conventional insulators often have good acoustic quality but only small piezoelectric effects, rendering the direct excitation, manipulation, and detection of the coherent SAWs challenging. The phonon pumping [17], i.e., the excitation of bulk sound waves in a high-quality acoustic insulator by the dynamics of a proximity magnetic layer via the magnetoelastic coupling [18,19], may be useful here. Bulk phonons in the insulator gadolinium gallium garnet (GGG) can couple two yttrium iron garnet (YIG) magnetic layers over millimeters [20,21].…”

A Quantum Tango between Magnons and Phonons

“…The hybridization was obtained by tuning the magnet's magnon mode with an external field so that its frequency matched one of the vibrational resonances of the nanomagnet. Under optimal orientation of the applied field with respect to the magnet, we reached a strong-coupling regime with C as high as 1.7 [8].…”