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arXiv 2407.08540cond-mat.mtrl-sci
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非对称缺陷分布在Pt/Co/Pt中产生体Dzyaloshinskii-Moriya相互作用

Asymmetric defect distribution generates bulk Dzyaloshinskii-Moriya interaction in Pt/Co/Pt

Nagoya University(名古屋大学);Institute of Materials and Systems for Sustainability, Nagoya University(名古屋大学材料系统可持续发展研究所)

Ayaka P. Ohki, Tatsuro Karino, Daigo Shimizu, Takeshi Kato, Daiki Oshima, Masahiro Nagao

AI总结:

研究揭示名义对称Pt/Co/Pt多层膜中体DMI源于非对称分布的位错,建立了缺陷工程调控DMI的策略,为自旋电子器件提供新设计原理。

摘要:

磁多层膜中的Dzyaloshinskii-Moriya相互作用(DMI)通过稳定和操控手性自旋纹理(包括手性畴壁和斯格明子),在自旋电子学应用中发挥关键作用。尽管非对称多层膜中的界面DMI已得到充分证实,但在原则上相反界面贡献应相互抵消的对称多层膜中,仍存在显著的DMI,该效应的微观起源尚未明确。本文中,我们展示了溅射制备的名义对称Pt/Co/Pt多层膜中存在缺陷介导的体DMI。利用洛伦兹透射电子显微镜和像差校正扫描透射电子显微镜,我们系统阐明了氩溅射气压对磁学和结构性质的影响:气压升高显著增强净DMI,从而稳定手性自旋纹理。原子尺度分析显示不存在清晰的界面,证实DMI主要起源于体相而非界面。然而,宏观成分不对称性非常微弱,且自旋轨道耦合无显著增强,不足以解释观测到的DMI。关键的是,我们对位错的统计分析揭示其空间分布存在强烈偏置,这些非对称分布的位错伴随局部原子位移,结合成分梯度,通过三站点Fert-Levy机制产生体DMI。我们的结果确立了缺陷工程作为控制DMI的有效策略,为自旋电子器件提供了新的设计原理。

英文摘要:

The Dzyaloshinskii-Moriya interaction (DMI) in magnetic multilayers plays a pivotal role in spintronic applications by enabling the stabilization and manipulation of chiral spin textures, including chiral domain walls and skyrmions. While interfacial DMI in asymmetric multilayers is well established, a substantial DMI persists in symmetric multilayers, where the opposing interface contributions should, in principle, cancel. The microscopic origin of this effect remains unresolved. Here, we show defect-mediated bulk DMI in sputtered nominally symmetric Pt/Co/Pt multilayers. Using Lorentz transmission electron microscopy and aberration-corrected scanning transmission electron microscopy, we systematically elucidate the effect of argon sputter gas pressure on both magnetic and structural properties. Increasing the pressure markedly enhances the net DMI, thereby stabilizing chiral spin textures. Atomic-scale analysis reveals the absence of welldefined interfaces, confirming that the DMI predominantly arises in the bulk rather than at the interfaces. However, macroscopic compositional asymmetries are remarkably weak, and spin-orbit coupling shows no significant enhancement, rendering them insufficient to account for the observed DMI. Crucially, our statistical analysis of dislocations uncovers a strongly biased spatial distribution. These asymmetrically distributed dislocations, accompanied by local atomic displacements, combined with compositional gradients, generate the bulk DMI through the three-site Fert-Levy mechanism. Our results establish defect engineering as an effective strategy for controlling DMI, offering new design principles for spintronic devices.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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