Effect of crystallinity on spin-orbit torque in 5$\textit{d}$ iridium oxide IrO$_{2}$

Fuente: arXiv
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Main Authors: Morimoto, Tetsuro, Ueda, Kohei, Shiogai, Junichi, Kida, Takanori, Hagiwara, Masayuki, Matsuno, Jobu
Format: Preprint
Published: 2025
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author Morimoto, Tetsuro
Ueda, Kohei
Shiogai, Junichi
Kida, Takanori
Hagiwara, Masayuki
Matsuno, Jobu
author_facet Morimoto, Tetsuro
Ueda, Kohei
Shiogai, Junichi
Kida, Takanori
Hagiwara, Masayuki
Matsuno, Jobu
contents The 5$\textit{d}$ transition-metal oxides provide an intriguing platform for generating an efficient spin current due to a unique electronic structure dominated by 5d electrons with strong spin-orbit coupling. Here, we report on the effect of crystallinity on current-driven spin-orbit torque (SOT) in binary 5$\textit{d}$ iridium oxide IrO$_{2}$ thin films by controlling amorphous, polycrystalline, and epitaxial states. By conducting harmonic Hall measurement in bilayers composed of ferromagnetic Co$_{20}$Fe$_{60}$B$_{20}$ and IrO$_{2}$, we find that dampinglike (DL) SOT is larger than fieldlike SOT for all the samples. We also demonstrate that both electrical resistivity and the DL SOT efficiency increase in order of epitaxial, polycrystalline, and amorphous IrO$_{2}$. Despite their different electrical conductivities, spin Hall conductivities of the three states of the IrO$_{2}$ layer are found to be nearly constant, which is consistent with the intrinsic regime of the spin Hall effect scaling relation. Our results highlight the important role that crystallinity plays in the spin-current generation, leading to the potential technological development of spintronic devices based on the 5$\textit{d}$ transition-metal oxides.
format Preprint
id arxiv_https___arxiv_org_abs_2505_10907
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Effect of crystallinity on spin-orbit torque in 5$\textit{d}$ iridium oxide IrO$_{2}$
Morimoto, Tetsuro
Ueda, Kohei
Shiogai, Junichi
Kida, Takanori
Hagiwara, Masayuki
Matsuno, Jobu
Materials Science
Mesoscale and Nanoscale Physics
The 5$\textit{d}$ transition-metal oxides provide an intriguing platform for generating an efficient spin current due to a unique electronic structure dominated by 5d electrons with strong spin-orbit coupling. Here, we report on the effect of crystallinity on current-driven spin-orbit torque (SOT) in binary 5$\textit{d}$ iridium oxide IrO$_{2}$ thin films by controlling amorphous, polycrystalline, and epitaxial states. By conducting harmonic Hall measurement in bilayers composed of ferromagnetic Co$_{20}$Fe$_{60}$B$_{20}$ and IrO$_{2}$, we find that dampinglike (DL) SOT is larger than fieldlike SOT for all the samples. We also demonstrate that both electrical resistivity and the DL SOT efficiency increase in order of epitaxial, polycrystalline, and amorphous IrO$_{2}$. Despite their different electrical conductivities, spin Hall conductivities of the three states of the IrO$_{2}$ layer are found to be nearly constant, which is consistent with the intrinsic regime of the spin Hall effect scaling relation. Our results highlight the important role that crystallinity plays in the spin-current generation, leading to the potential technological development of spintronic devices based on the 5$\textit{d}$ transition-metal oxides.
title Effect of crystallinity on spin-orbit torque in 5$\textit{d}$ iridium oxide IrO$_{2}$
topic Materials Science
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2505.10907