Long-Time-Scale Magnetization Ordering Induced by an Adsorbed Chiral Monolayer on Ferromagnets
Long-Time-Scale Magnetization Ordering Induced by an Adsorbed Chiral Monolayer on Ferromagnets
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DOI：
10.1021/acsnano.1c00455
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发表时间：
2021-02-16
期刊：
影响因子：
17.1
通讯作者：
Bar-Gill, N.
中科院分区：
文献类型：
--
作者：
Meirzada, I;Sukenik, N.;Bar-Gill, N.
当电子通过手性分子时，电荷的动量和自旋之间很可能存在关联，从而导致自旋极化电流。这种现象被称为手性诱导自旋选择性（CISS）效应。最近最令人惊讶的实验结果之一是，具有垂直各向异性的铁磁体中的磁化反转可以仅通过化学吸附手性分子单层来实现，而无需施加任何电流或外磁场。这一结果提出了目前悬而未决的问题，这种效果是否是由于键合事件，由铁磁体，或交换相互作用稳定的长时间尺度的影响。在这项工作中，我们已经进行了矢量磁场测量的磁化重取向的铁磁层表现出垂直各向异性，由于CISS使用氮空位中心在金刚石，并遵循这种效果的时间动态。同时，我们测量了分子单层的倾斜角，以找到磁化重取向的时间依赖性和分子单层的倾斜角的变化之间的相关性。我们已经确定，磁化方向的变化对应于分子单层倾斜角的变化，提供了证据的诱导磁化重取向的长时间尺度特性。这表明CISS效应在很长的时间尺度上都有影响，我们将其归因于交换相互作用。这些结果提供了重要的洞察CISS效应的基本过程，有助于实现CISS在国家的最先进的应用，如自旋电子和磁存储器件。
When an electron passes through a chiral molecule, there is a high probability for correlation between the momentum and spin of the charge, thus leading to a spin polarized current. This phenomenon is known as the chiral-induced spin selectivity (CISS) effect. One of the most surprising experimental results recently demonstrated is that magnetization reversal in a ferromagnet with perpendicular anisotropy can be realized solely by chemisorbing a chiral molecular monolayer without applying any current or external magnetic field. This result raises the currently open question of whether this effect is due to the bonding event, held by the ferromagnet, or a long-time-scale effect stabilized by exchange interactions. In this work we have performed vectorial magnetic field measurements of the magnetization reorientation of a ferromagnetic layer exhibiting perpendicular anisotropy due to CISS using nitrogen-vacancy centers in diamond and followed the time dynamics of this effect. In parallel, we have measured the molecular monolayer tilt angle in order to find a correlation between the time dependence of the magnetization reorientation and the change of the tilt angle of the molecular monolayer. We have identified that changes in the magnetization direction correspond to changes of the molecular monolayer tilt angle, providing evidence for a long-time-scale characteristic of the induced magnetization reorientation. This suggests that the CISS effect has an effect over long time scales which we attribute to exchange interactions. These results offer significant insights into the fundamental processes underlying the CISS effect, contributing to the implementation of CISS in state-of-the-art applications such as spintronic and magnetic memory devices.