[论文解读] Phononic Switching of Magnetization by the Ultrafast Barnett Effect

C. S. Davies, F. G. N. Fennema+4 more|arXiv (Cornell University)|May 19, 2023

Magnetic properties of thin films被引用 11

一句话总结

该研究表明，通过 ultrafast Barnett effect 驱动、由共振激发的圆偏振光声子在顺磁基底中产生的效应，可以永久逆转安装在基底上的异质结构的磁态，切换由声子手性控制。

ABSTRACT

The Barnett effect, discovered more than a century ago, describes how an inertial body with otherwise zero net magnetic moment acquires spontaneous magnetization when mechanically spinning. Breakthrough experiments have recently shown that an ultrashort laser pulse destroys the magnetization of an ordered ferromagnet within hundreds of femtoseconds, with the spins losing angular momentum to circularly-polarized optical phonons as part of the ultrafast Einstein-de Haas effect. However, the prospect of using such high-frequency vibrations of the lattice to reciprocally switch magnetization in a nearby magnetic medium has not yet been experimentally explored. Here we show that the spontaneous magnetization temporarily gained via the ultrafast Barnett effect, through the resonant excitation of circularly-polarized optical phonons in paramagnetic substrates, can be used to permanently reverse the magnetic state of the substrate-mounted heterostructure. With the handedness of the phonons steering the direction of magnetic switching, the ultrafast Barnett effect offers a selective and potentially universal method for exercising ultrafast non-local control over magnetic order.

研究动机与目标

• 推动利用高频晶格振动实现磁序的超快非局部控制。
• 证明 ultrafast Barnett effect 能在异质结构中诱导永久磁化切换。
• 探究圆偏振光声子是否能通过声子手性选择性引导磁态。

提出的方法

• 在顺磁基底中共振激发圆偏振光声子。
• 通过 ultrafast Barnett effect 诱导自发磁化。
• 将声子驱动的磁化耦合到安装在基底上的异质结构以实现切换。
• 观察磁态的永久性反转，受声子手性控制。

实验结果

研究问题

• RQ1 是否能够由共振圆偏振声子驱动的 ultrafast Barnett effect 在附近的磁性介质中诱导永久磁化变化？
• RQ2 磁性切换的方向是否可以被激发声子的手性控制？
• RQ3 这种声子介导的机制是否提供了一种普遍的、超快的非局部磁控制方法？

主要发现

• 通过 ultrafast Barnett effect 获得的自发磁化可用于永久逆转异质结构的磁状态。
• 切换方向由激发的声子手性引导。
• 该方法引入了一种具有选择性、潜在普遍性的超快非局部磁序控制方法。