Magnon-phonon relaxation in yttrium iron garnet from first principles
Magnon-phonon relaxation in yttrium iron garnet from first principles
复制标题
从第一原理看钇铁石榴石中的磁振子-声子弛豫
DOI：
10.1103/physrevb.96.174416
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发表时间：
2017-11-14
影响因子：
3.7
通讯作者：
Xia, Ke
中科院分区：
文献类型：
--
作者：
Liu, Yi;Xie, Li-Shan;Xia, Ke
将自旋波激发的理论计算方法与有限温度模型相联合收割机，从第一性原理出发，计算了钇铁石榴石（YIG）中的磁振子-声子弛豫时间。磁振子激发的有限寿命是由YIG中磁性原子交换相互作用的涨落引起的。在室温下，磁振子谱有明显的展宽，可以用来定量提取磁振子-声子弛豫时间。后者是基于YIG的自旋电子学研究中非常重要的唯象参数。我们发现，在长波区，光学磁振子的磁振子-声子弛豫时间是一个常数，而声学磁振子的磁振子-声子弛豫时间与1/k^2成正比。
We combine the theoretical method of calculating spin wave excitation with the finite-temperature modeling and calculate the magnon-phonon relaxation time in the technologically important material Yttrium iron garnet (YIG) from first principles. The finite lifetime of magnon excitation is found to arise from the fluctuation of the exchange interaction of magnetic atoms in YIG. At room temperature, the magnon spectra have significant broadening that is used to extract the magnon-phonon relaxation time quantitatively. The latter is a phenomenological parameter of great importance in YIG-based spintronics research. We find that the magnon-phonon relaxation time for the optical magnon is a constant while that for the acoustic magnon is proportional to $1/k^2$ in the long-wavelength regime.