Obinata Sora, Iimori Riku, Ohnishi Kohei, Kimura Takashi
Department of Physics, Kyushu University, 744 Motooka, Fukuoka, 819-0395, Japan.
Sci Rep. 2022 Mar 2;12(1):3467. doi: 10.1038/s41598-022-06784-6.
A dynamical spin injection based on the ferromagnetic resonance in a ferromagnetic/nonmagnetic bi-layered structure, is a powerful mean for generating and manipulating the spin current. Although the mechanism of the dynamical spin injection is mainly attributed to the spin pumping, the detailed mechanism and the quantitative understanding for related phenomena are still controversial. As an another important contribution to the dynamical spin injection, the heating effect due to the resonant precessional motion of the magnetization is pointed out recently. In order to quantify the contribution from the heating effect, we here investigate the dynamical spin injection in a CoFeB/Pt/CoFeB trilayer. Although the contribution from the spin pumping diminishes because of the symmetric spin injection from the upper and lower interfaces, a significant inverse spin Hall voltage has been clearly observed. We show that the observed voltage can be quantitatively understood by the thermal spin injection due to a heating effect during the ferromagnetic resonance. A proper combination between the spin pumping and the heat-flow control in the multi-layered system is a key for the efficient dynamical spin injection.
基于铁磁/非磁双层结构中铁磁共振的动态自旋注入，是产生和操纵自旋电流的一种强大手段。尽管动态自旋注入的机制主要归因于自旋泵浦，但相关现象的详细机制和定量理解仍存在争议。作为对动态自旋注入的另一项重要贡献，最近指出了由于磁化的共振进动运动而产生的热效应。为了量化热效应的贡献，我们在此研究了CoFeB/Pt/CoFeB三层结构中的动态自旋注入。尽管由于上下界面的对称自旋注入，自旋泵浦的贡献减弱，但仍清晰地观察到了显著的逆自旋霍尔电压。我们表明，通过铁磁共振期间的热效应引起的热自旋注入，可以对观察到的电压进行定量理解。多层系统中自旋泵浦和热流控制的适当组合是实现高效动态自旋注入的关键。
