Thickness-dependent magnon spin transport in antiferromagnetic insulators: Crossover from quasi-three-dimensional to quasi-two-dimensional regimes

Fuente: arXiv
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Autores principales: Myhre, Mathias Åsan, Brehm, Verena, Delvaux, Thomas, Brataas, Arne, Qaiumzadeh, Alireza
Formato: Preprint
Publicado: 2025
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author Myhre, Mathias Åsan
Brehm, Verena
Delvaux, Thomas
Brataas, Arne
Qaiumzadeh, Alireza
author_facet Myhre, Mathias Åsan
Brehm, Verena
Delvaux, Thomas
Brataas, Arne
Qaiumzadeh, Alireza
contents Motivated by the recent observation of giant room-temperature magnon spin conductivity in an ultrathin ferromagnetic insulator [X.-Y. Wei et al., Nat. Mater. 21, 1352 (2022)], we investigate thickness-dependent magnon spin transport in thin antiferromagnetic insulators (AFIs). We study the prototypical AFI hematite, known for its exceptionally low magnetic damping and two distinct magnetic phases: a low-temperature uniaxial easy-axis phase and a high-temperature biaxial easy-plane phase. Using stochastic micromagnetic simulations, we investigate thickness-dependent magnon spin transport across both magnetic phases. Our results uncover a crossover from quasi-three-dimensional to quasi-two-dimensional magnon spin transport at a critical thickness, determined by the frequency or energy of the excited magnons. Below this critical thickness, we observe a pronounced enhancement in the magnon diffusion length in both magnetic phases. This rise is attributed to a change in the effective magnon density of states, reflecting the reduced phase space available for scattering in the thinner, quasi-two-dimensional regime. Understanding and controlling long-distance magnon spin transport in AFIs is crucial for developing next-generation spintronic nanodevices, especially as materials approach the two-dimensional limit.
format Preprint
id arxiv_https___arxiv_org_abs_2509_03941
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Thickness-dependent magnon spin transport in antiferromagnetic insulators: Crossover from quasi-three-dimensional to quasi-two-dimensional regimes
Myhre, Mathias Åsan
Brehm, Verena
Delvaux, Thomas
Brataas, Arne
Qaiumzadeh, Alireza
Mesoscale and Nanoscale Physics
Materials Science
Motivated by the recent observation of giant room-temperature magnon spin conductivity in an ultrathin ferromagnetic insulator [X.-Y. Wei et al., Nat. Mater. 21, 1352 (2022)], we investigate thickness-dependent magnon spin transport in thin antiferromagnetic insulators (AFIs). We study the prototypical AFI hematite, known for its exceptionally low magnetic damping and two distinct magnetic phases: a low-temperature uniaxial easy-axis phase and a high-temperature biaxial easy-plane phase. Using stochastic micromagnetic simulations, we investigate thickness-dependent magnon spin transport across both magnetic phases. Our results uncover a crossover from quasi-three-dimensional to quasi-two-dimensional magnon spin transport at a critical thickness, determined by the frequency or energy of the excited magnons. Below this critical thickness, we observe a pronounced enhancement in the magnon diffusion length in both magnetic phases. This rise is attributed to a change in the effective magnon density of states, reflecting the reduced phase space available for scattering in the thinner, quasi-two-dimensional regime. Understanding and controlling long-distance magnon spin transport in AFIs is crucial for developing next-generation spintronic nanodevices, especially as materials approach the two-dimensional limit.
title Thickness-dependent magnon spin transport in antiferromagnetic insulators: Crossover from quasi-three-dimensional to quasi-two-dimensional regimes
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2509.03941