Abstract The manipulation of magnetization in a metallic ferromagnet by using optical helicity has been much attracted attention for future opto-spintronic devices. The optical helicity–induced torques on the magnetization, optical spin torque, have been observed in ferromagnetic thin films recently. However, the interfacial effect of the optical spin torque in ferromagnet/nonmagnetic heavy metal heterostructures have not been addressed so far, which are widely utilized to efficiently control magnetization via electrical means. Here, we studied optical spin torque vectors in the ferromagnet/nonmagnetic heavy metal heterostructures and observed that in-plane field-like optical spin torque was significantly increased with decreasing ferromagnetic layer thicknesses. The interfacial field-like optical spin torque was explained by the optical Rashba–Edelstein effect caused by the structural inversion symmetry breaking. This work will aid in the efficient optical manipulation of thin film nanomagnets using optical helicity.

中文翻译：

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铁磁体/重金属异质结构中界面诱导的类场光学自旋力矩

摘要 利用光学螺旋性对金属铁磁体中的磁化进行操纵已成为未来光自旋电子器件的关注焦点。最近在铁磁薄膜中观察到光学螺旋引起的磁化转矩，光学自旋转矩。然而，迄今为止尚未解决铁磁体/非磁性重金属异质结构中光学自旋扭矩的界面效应，其被广泛用于通过电手段有效控制磁化。在这里，我们研究了铁磁体/非磁性重金属异质结构中的光学自旋力矩矢量，并观察到随着铁磁层厚度的减小，面内场状光学自旋力矩显着增加。类似界面场的光学自旋扭矩可以通过结构反转对称性破坏引起的光学 Rashba-Edelstein 效应来解释。这项工作将有助于使用光学螺旋对薄膜纳米磁铁进行有效的光学操作。