Edwards Eric R J, Nembach Hans T, Shaw Justin M
Quantum Electromagnetics Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305.
Phys Rev Appl. 2019;11. doi: 10.1103/PhysRevApplied.11.054036.
We measure the dynamic properties of CoFe thin films grown by dc magnetron sputtering. Using ferromagnetic resonance spectroscopy, we demonstrate an ultralow damping parameter in the out-of-plane configuration of < 0.0013, whereas for the in-plane configuration we find a minimum damping of < 0.0020. In both cases, we observe low inhomogeneous linewidth broadening in macroscopic films. We observe a minimum full-width half-maximum linewidth of 1 mT at 10 GHz resonance frequency for a 12 nm thick film. We characterize the morphology and structure of these films as a function of seed layer combinations and find large variation of the qualitative behavior of the in-plane linewidth vs. resonance frequency. Finally, we use wavevector-dependent Brillouin light scattering spectroscopy to characterize the spin-wave dispersion at wave vectors up to 23 μm.
我们测量了通过直流磁控溅射生长的CoFe薄膜的动态特性。利用铁磁共振光谱，我们证明了在面外配置中具有<0.0013的超低阻尼参数，而在面内配置中我们发现最小阻尼<0.0020。在这两种情况下，我们在宏观薄膜中都观察到低非均匀线宽展宽。对于12nm厚的薄膜，我们在10GHz共振频率下观察到最小半高全宽线宽为1mT。我们将这些薄膜的形态和结构表征为籽晶层组合的函数，并发现面内线宽与共振频率的定性行为有很大变化。最后，我们使用波矢相关的布里渊光散射光谱来表征波矢高达23μm时的自旋波色散。
