Interaction of subthermal magnons and phonons and their role for the transverse Seebeck effect

我们计划通过施加磁振子或声子温度的梯度来研究吉赫兹频率区间内亚热磁子和声子之间的相互作用，以了解它们在横向自旋塞贝克效应(TSSE)中的作用。特别关注能量接近其光谱最小值的YIG薄膜中的磁子，而非相干磁子和玻色-爱因斯坦凝聚体(BEC)都将被讨论。我们将研究这些磁子在温度梯度下的性质，以及在千兆赫兹频率下声自旋泵浦的影响。TSSE的时间分辨研究将在两个模型系统中进行：YIG/铂和NiFe/铂，而相应的磁振子温度梯度将通过微波泵浦或自旋电流注入产生。利用磁振子-磁振子和磁振子-声子时间的差异，时间分辨测量将阐明亚热磁振子在这一效应中的作用。

We plan to investigate interaction between subthermal magnons and phonons in the gigahertz frequency interval by applying a gradient of either magnon or phonon temperatures with targeting the understanding of their role in the transverse spin Seebeck effect (TSSE). Particular attention will be paid to magnons in YIG films with energies close to the minimum of their spectrum, whereas both incoherent magnons and Bose-Einstein condensates (BEC) will be addressed. Properties of these magnons in thermal gradient as well as under influence of acoustic spin pumping at gigahertz frequencies will be studied. Time-resolved studies of TSSE will be performed in two model systems: YIG/Pt and NiFe/Pt, whereas gradients of magnon temperature will be created using microwave pumping or spin-current injections, correspondingly. Taking advantage of a difference between magnon-magnon and magnon-phonon times, time-resolved measurements will clarify the role of subthermal magnons in the effect.