Investigation of magnetization dynamics in spin-wave metamaterials

我们建立了一个由相互作用的磁性纳米颗粒组成的自旋波超材料中磁矩进动的解析模型。结果表明，吉尔伯特阻尼因子可以由超材料的结构来控制。此外，还得到了自旋波超材料中自旋扭矩振荡的宏观阻尼因子的解析方程。方程表明，有效阻尼因子与自旋电流有关，而自旋扭矩振荡的频率与自旋电流无关。此外，我们还在实验上成功地制备了由铁磁性金属制成的人工手性结构，并观察到了电子自旋共振光谱中的特征信号。目前的研究是通过自旋波将超材料和自旋电子学结合在一起。

We constructed an analytical model for precession of a magnetic moment in spin-wave metamaterials consisting of interacting magnetic nanoparticles. It is revealed that the Gilbert damping factor can be controlled by the structure of the metamaterials. Additionally, analytical equations of the macroscopic damping factor were obtained for spin-torque oscillation in the spin-wave metamaterials. The equations indicated that the effective damping factor is dependent on the spin currents whereas the frequency of spin torque oscillation is independent of the spin currents. Moreover, we have experimentally succeeded in fabricating artificial chiral structures made of ferromagnetic-metals and observing a characteristic signal in electron spin resonance spectra. The present study is bringing together metamaterials and spintronics via spin-waves.