Pirro P, Sebastian T, Brächer T, Serga A A, Kubota T, Naganuma H, Oogane M, Ando Y, Hillebrands B
Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.
Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany and Graduate School Materials Science in Mainz, Gottlieb-Daimler-Straße 47, Germany.
Phys Rev Lett. 2014 Nov 28;113(22):227601. doi: 10.1103/PhysRevLett.113.227601. Epub 2014 Nov 26.
The nonlinear decay of propagating spin waves in the low-Gilbert-damping Heusler film Co_{2}Mn_{0.6}Fe_{0.4}Si is reported. Here, two initial magnons with frequency f_{0} scatter into two secondary magnons with frequencies f_{1} and f_{2}. The most remarkable observation is that f_{1} stays fixed if f_{0} is changed. This indicates, that the f_{1} magnon mode has the lowest instability threshold, which, however, cannot be understood if only Gilbert damping is present. We show that the observed behavior is caused by interaction of the magnon modes f_{1} and f_{2} with the thermal magnon bath. This evidences a significant contribution of the intrinsic magnon-magnon scattering mechanisms to the magnetic damping in high-quality Heusler compounds.
报道了在低吉尔伯特阻尼的赫斯勒薄膜Co₂Mn₀.₆Fe₀.₄Si中传播自旋波的非线性衰减。在这里，两个频率为f₀的初始磁振子散射成两个频率为f₁和f₂的次级磁振子。最显著的观察结果是，如果f₀改变，f₁保持不变。这表明，f₁磁振子模式具有最低的不稳定性阈值，然而，如果仅存在吉尔伯特阻尼，这是无法理解的。我们表明，观察到的行为是由磁振子模式f₁和f₂与热磁振子库的相互作用引起的。这证明了本征磁振子-磁振子散射机制对高质量赫斯勒化合物中的磁阻尼有显著贡献。
