Université de Lorraine, CNRS, IJL, Nancy, France.
Anhui High Reliability Chips Engineering Laboratory, Hefei Innovation Research Institute, Beihang University, Hefei, China.
Nat Mater. 2023 Jun;22(6):725-730. doi: 10.1038/s41563-023-01499-z. Epub 2023 Mar 9.
The discovery of spin-transfer torque (STT) enabled the control of the magnetization direction in magnetic devices in nanoseconds using an electrical current. Ultrashort optical pulses have also been used to manipulate the magnetization of ferrimagnets at picosecond timescales by bringing the system out of equilibrium. So far, these methods of magnetization manipulation have mostly been developed independently within the fields of spintronics and ultrafast magnetism. Here we show optically induced ultrafast magnetization reversal taking place within less than a picosecond in rare-earth-free archetypal spin valves of [Pt/Co]/Cu/[Co/Pt] commonly used for current-induced STT switching. We find that the magnetization of the free layer can be switched from a parallel to an antiparallel alignment, as in STT, indicating the presence of an unexpected, intense and ultrafast source of opposite angular momentum in our structures. Our findings provide a route to ultrafast magnetization control by bridging concepts from spintronics and ultrafast magnetism.
自旋转移扭矩（STT）的发现使得可以在纳秒级使用电流控制磁性器件中的磁化方向。超短光脉冲也被用于通过使系统脱离平衡来在皮秒时间尺度上操纵亚铁磁体的磁化。到目前为止，这些磁化操纵方法主要是在自旋电子学和超快磁学领域中独立开发的。在这里，我们展示了在通常用于电流诱导 STT 切换的[Pt/Co]/Cu/[Co/Pt]无稀土典型自旋阀中，在不到 1 皮秒的时间内发生的光诱导超快磁化反转。我们发现自由层的磁化可以从平行切换到反平行排列，就像在 STT 中一样，这表明在我们的结构中存在一个意想不到的、强烈的超快的相反角动量源。我们的发现通过桥接自旋电子学和超快磁学的概念，为超快磁化控制提供了一种途径。
