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arXiv 2305.03368cond-mat.mes-hall
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反铁磁 Mn$_2$Au 中的非线性太赫兹 Néel 自旋轨道转矩

Nonlinear terahertz Néel spin-orbit torques in antiferromagnetic Mn$_2$Au

Yannic Behovits, Alexander L. Chekhov, Stanislav Yu. Bodnar, Oliver Gueckstock, Sonka Reimers, Tom S. Seifert, Martin Wolf, Olena Gomonay, Mathias Kläui, Martin… 展开作者

Yannic Behovits, Alexander L. Chekhov, Stanislav Yu. Bodnar, Oliver Gueckstock, Sonka Reimers, Tom S. Seifert, Martin Wolf, Olena Gomonay, Mathias Kläui, Martin Jourdan, Tobias Kampfrath

AI总结:

该研究用相位锁定单周期太赫兹脉冲激发 Mn$_2$Au 薄膜,观测到超快类场 NSOT 及高场下高达30°的非线性 Néel 矢量偏转,证明1 ps内90°相干翻转有望实现。

摘要:

反铁磁体在以最小热耗散实现磁序超快相干翻转方面具有巨大潜力。在 Mn$_2$Au 和 CuMnAs 等新型材料中,电场而非磁场可通过 Néel 自旋轨道转矩(NSOT)控制反铁磁序;然而,NSOT 尚未在超快时间尺度上被观测到。这里,我们使用相位锁定的单周期太赫兹电磁脉冲激发 Mn$_2$Au 薄膜,并利用飞秒磁光探针监测自旋响应。我们观测到的信号在对称性、动力学、太赫兹场标度以及对样品结构的依赖方面,均与由类场太赫兹 NSOT 驱动的均匀面内反铁磁磁振子完全一致,其转矩电导为 (150±50) cm$^2$/A s。当入射太赫兹电场超过 500 kV/cm 时,我们发现显著的非线性动力学,Néel 矢量发生高达 30° 的大幅偏转。我们的数据与微磁模型高度吻合;该模型表明,在 1 ps 内实现 Néel 矢量的完全相干 90° 翻转已近在咫尺。

英文摘要:

Antiferromagnets have large potential for ultrafast coherent switching of magnetic order with minimum heat dissipation. In novel materials such as Mn$_2$Au and CuMnAs, electric rather than magnetic fields may control antiferromagnetic order by Néel spin-orbit torques (NSOTs), which have, however, not been observed on ultrafast time scales yet. Here, we excite Mn$_2$Au thin films with phase-locked single-cycle terahertz electromagnetic pulses and monitor the spin response with femtosecond magneto-optic probes. We observe signals whose symmetry, dynamics, terahertz-field scaling and dependence on sample structure are fully consistent with a uniform in-plane antiferromagnetic magnon driven by field-like terahertz NSOTs with a torkance of (150$\pm$50) cm$^2$/A s. At incident terahertz electric fields above 500 kV/cm, we find pronounced nonlinear dynamics with massive Néel-vector deflections by as much as 30°. Our data are in excellent agreement with a micromagnetic model which indicates that fully coherent Néel-vector switching by 90° within 1 ps is within close reach.

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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