Acoustic orbital Hall effect and orbital pumping in light-metal-ferromagnet bilayers

Fuente: arXiv
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Autori principali: Wu, Mingxing, Ding, Shilei, Matsumoto, Hiroki, Gambardella, Pietro
Natura: Preprint
Pubblicazione: 2025
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author Wu, Mingxing
Ding, Shilei
Matsumoto, Hiroki
Gambardella, Pietro
author_facet Wu, Mingxing
Ding, Shilei
Matsumoto, Hiroki
Gambardella, Pietro
contents Orbital currents provide a new degree of freedom for controlling magnetism, yet their interaction with lattice dynamics remains largely unexplored. Here we report a systematic investigation of the acoustic orbital Hall effect in light metals such as Ti and Cr, where surface acoustic waves generate orbital currents through phonon-orbital coupling. The acoustic orbital current in Ti exhibits higher efficiency and longer diffusion length compared to the acoustic spin current in Pt. The sign and magnitude of the rectified acoustic voltages in nonmagnetic (Ti, Cr)/ferromagnetic (Ni, Co, Fe$_x$Co$_{1-x}$) bilayers are determined by the product of orbital-to-spin conversion and magnetoelastic coupling efficiencies of the ferromagnet. Additionally, we find evidence for acoustic orbital pumping, whereby the excitation of ferromagnetic resonance by surface acoustic waves injects an orbital current from the ferromagnet into the nonmagnet. These results establish lattice dynamics as an efficient driver of orbital transport, opening opportunities for low-dissipation orbitronic devices that harness and sense phonons.
format Preprint
id arxiv_https___arxiv_org_abs_2511_02388
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Acoustic orbital Hall effect and orbital pumping in light-metal-ferromagnet bilayers
Wu, Mingxing
Ding, Shilei
Matsumoto, Hiroki
Gambardella, Pietro
Mesoscale and Nanoscale Physics
Orbital currents provide a new degree of freedom for controlling magnetism, yet their interaction with lattice dynamics remains largely unexplored. Here we report a systematic investigation of the acoustic orbital Hall effect in light metals such as Ti and Cr, where surface acoustic waves generate orbital currents through phonon-orbital coupling. The acoustic orbital current in Ti exhibits higher efficiency and longer diffusion length compared to the acoustic spin current in Pt. The sign and magnitude of the rectified acoustic voltages in nonmagnetic (Ti, Cr)/ferromagnetic (Ni, Co, Fe$_x$Co$_{1-x}$) bilayers are determined by the product of orbital-to-spin conversion and magnetoelastic coupling efficiencies of the ferromagnet. Additionally, we find evidence for acoustic orbital pumping, whereby the excitation of ferromagnetic resonance by surface acoustic waves injects an orbital current from the ferromagnet into the nonmagnet. These results establish lattice dynamics as an efficient driver of orbital transport, opening opportunities for low-dissipation orbitronic devices that harness and sense phonons.
title Acoustic orbital Hall effect and orbital pumping in light-metal-ferromagnet bilayers
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2511.02388