Magnetoelastic modes and lifetime of magnons in thin yttrium iron garnet films
Magnetoelastic modes and lifetime of magnons in thin yttrium iron garnet films
复制标题
DOI：
10.1103/physrevb.89.184413
复制
发表时间：
2014-02
影响因子：
3.7
通讯作者：
Andreas Ruckriegel;P. Kopietz;D. Bozhko;O. Serga;B. Hillebrands
中科院分区：
文献类型：
--
作者：
Andreas Ruckriegel;P. Kopietz;D. Bozhko;O. Serga;B. Hillebrands
我们计算了自旋-晶格耦合对由钇铁石榴石组成的铁磁薄膜的磁振子谱的影响。磁子-声子杂化在自旋动力学结构因子中产生了一个特征极小值，这在定量上与最近的布里渊光散射实验一致。我们还表明，在室温下，声子对磁振子阻尼的贡献表现出相当复杂的动量依赖性：在交换区，磁振子阻尼主要由切伦科夫型散射过程主导，而在长波长偶极区，这些过程占次主导地位，磁振子阻尼小两个数量级。我们用偶极态中磁振子弛豫的实际测量来补充我们的计算。我们的理论为最近的一个实验提供了一个简单的解释，该实验探测了钇铁石榴石中磁振子和声子气体的不同温度。
We calculate the effects of the spin-lattice coupling on the magnon spectrum of thin ferromagnetic films consisting of the magnetic insulator yttrium-iron garnet. The magnon-phonon hybridisation generates a characteristic minimum in the spin dynamic structure factor which quantitatively agrees with recent Brillouin light scattering experiments. We also show that at room temperature the phonon contribution to the magnon damping exhibits a rather complicated momentum dependence: In the exchange regime the magnon damping is dominated by Cherenkov type scattering processes, while in the long-wavelength dipolar regime these processes are subdominant and the magnon damping is two orders of magnitude smaller. We supplement our calculations by actual measurements of the magnon relaxation in the dipolar regime. Our theory provides a simple explanation of a recent experiment probing the different temperatures of the magnon and phonon gases in yttrium-iron garnet.