Generation and Imaging of Magnetoacoustic Waves over Millimeter Distances

Casals, Blai; Statuto, Nahuel; Foerster, Michael; Hernández-Mínguez, A.; Cichelero, Rafael; Manshausen, Peter; Mandziak, Anna; Aballe, Lucía; Hernández, J. M.; Maciá, Ferran

doi:10.1103/physrevlett.124.137202

Cited by 62 publications

(48 citation statements)

References 32 publications

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“…The suggested approach is applicable for the manipulation of propagating magnon polarons. While the ability of surface acoustic waves to carry magnons across extremely long distances has been recently demonstrated in the weak coupling regime [50], the strong magnon-phonon coupling will enrich collective magnon-phonon transport by pronounced nonreciprocity and give access to the manipulation of the polarization of surface acoustic waves [48]. For instance, at certain direction of external magnetic field, the attenuation and propagation velocity are expected to be different for the magnon polarons propagating in opposite directions along the reciprocal lattice vector of the nanograting [51][52][53].…”

Section: Discussionmentioning

confidence: 99%

Magnon polaron formed by selectively coupled coherent magnon and phonon modes of a surface patterned ferromagnet

et al. 2020

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Strong coupling between two quanta of different excitations leads to the formation of a hybridized state which paves a way for exploiting new degrees of freedom to control phenomena with high efficiency and precision. A magnon polaron is the hybridized state of a phonon and a magnon, the elementary quanta of lattice vibrations and spin waves in a magnetically-ordered material. A magnon polaron can be formed at the intersection of the magnon and phonon dispersions, where their frequencies coincide.The observation of magnon polarons in the time domain has remained extremely challenging because the weak interaction of magnons and phonons and their short lifetimes jeopardize the strong coupling required for the formation of a hybridized state. Here, we overcome these limitations by spatial matching of magnons and phonons in a metallic ferromagnet with a nanoscale periodic surface pattern.The spatial overlap of the selected phonon and magnon modes formed in the periodic ferromagnetic structure results in a high coupling strength which, in combination with their long lifetimes allows us to find clear evidence of an optically excited magnon polaron. We show that the symmetries of the localized magnon and phonon states play a crucial role in the magnon polaron formation and its manifestation in the optically excited magnetic transients.

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Section: Discussionmentioning

confidence: 99%

Magnon polaron formed by selectively coupled coherent magnon and phonon modes of a surface patterned ferromagnet

et al. 2020

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“…Long-range transfer of angular momentum between two YIG layers separated by a thick substrate 20 is realized by the magnon–phonon coupling 21 . Direct imaging and quantification of both standing and propagating acoustomagnetic waves were presented in hybrid structures consisting of a piezoelectric substrate underneath Ni 22 . This way, magnon–phonon coupling and excitation by a large-area interdigital transducer (IDT) allowed to transport spin information over a macroscopic distance at specific IDT frequencies 22 .…”

Section: Introductionmentioning

confidence: 99%

Long decay length of magnon-polarons in BiFeO3/La0.67Sr0.33MnO3 heterostructures

Zhang

Chen

et al. 2021

Nat Commun

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Magnons can transfer information in metals and insulators without Joule heating, and therefore are promising for low-power computation. The on-chip magnonics however suffers from high losses due to limited magnon decay length. In metallic thin films, it is typically on the tens of micrometre length scale. Here, we demonstrate an ultra-long magnon decay length of up to one millimetre in multiferroic/ferromagnetic BiFeO3(BFO)/La0.67Sr0.33MnO3(LSMO) heterostructures at room temperature. This decay length is attributed to a magnon-phonon hybridization and is more than two orders of magnitude longer than that of bare metallic LSMO. The long-distance modes have high group velocities of 2.5 km s−1 as detected by time-resolved Brillouin light scattering. Numerical simulations suggest that magnetoelastic coupling via the BFO/LSMO interface hybridizes phonons in BFO with magnons in LSMO to form magnon-polarons. Our results provide a solution to the long-standing issue on magnon decay lengths in metallic magnets and advance the bourgeoning field of hybrid magnonics.

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“…Recent studies showed that bulk phonons in the insulator gadolinium gallium garnet (GGG) can couple two YIG magnetic layers over millimeters [11][12][13][14], raising the possibility of using phonon currents to transfer spin information in nonmagnetic insulators. The surface (Rayleigh) acoustic waves (SAWs), known as excellent sources to pump spin waves via acoustic spin pumping [15][16][17][18][19][20][21], can propagate a longer distance with a larger group velocity [22,23] and thus is promising to transport spin information.…”

Section: Introductionmentioning

confidence: 99%

Nonreciprocal surface magnetoelastic dynamics

2020

Phys. Rev. B

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Motivated by recent experiments, we investigate the nonreciprocal magnetoelastic interaction between the surface acoustic phonons of dielectric nonmagnetic substrates and magnons of proximity nanomagnets. The magnetization dynamics exerts rotating forces at the edges of the nanomagnet that causes the nonreciprocal interaction with surface phonons due to its rotation-momentum locking. This coupling induces the nonreciprocity of the surface phonon transmission and a nearly complete phonon diode effect by several (tens of) magnetic nanowires of high (ordinary) magnetic quality. Phase-sensitive microwave transmission is also nonreciprocal that can pick up clear signals of the coherent phonons excited by magnetization dynamics. Nonreciprocal pumping of phonons by precessing magnetization is predicted using Landauer-Büttiker formalism.

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Generation and Imaging of Magnetoacoustic Waves over Millimeter Distances

Cited by 62 publications

References 32 publications

Magnon polaron formed by selectively coupled coherent magnon and phonon modes of a surface patterned ferromagnet

Magnon polaron formed by selectively coupled coherent magnon and phonon modes of a surface patterned ferromagnet

Long decay length of magnon-polarons in BiFeO3/La0.67Sr0.33MnO3 heterostructures

Nonreciprocal surface magnetoelastic dynamics

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