Barker Joseph, Bauer Gerrit E W
Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
WPI-AIMR, Tohoku University, Sendai 980-8577, Japan.
Phys Rev Lett. 2016 Nov 18;117(21):217201. doi: 10.1103/PhysRevLett.117.217201. Epub 2016 Nov 14.
The magnetic insulator yttrium iron garnet can be grown with near perfection and is therefore and ideal conduit for spin currents. It is a complex material with 20 magnetic moments in the unit cell. In spite of being a ferrimagnet, YIG is almost always modeled as a simple ferromagnet with a single spin wave mode. We use the method of atomistic spin dynamics to study the temperature evolution of the full spin wave spectrum, in quantitative agreement with neutron scattering experiments. The antiferromagnetic or optical mode is found to suppress the spin Seebeck effect at room temperature and beyond due to thermally pumped spin currents with opposite polarization to the ferromagnetic mode.
磁性绝缘体钇铁石榴石能够近乎完美地生长，因此是自旋电流的理想传导介质。它是一种复杂材料，晶胞中有20个磁矩。尽管钇铁石榴石是一种亚铁磁体，但几乎总是被建模为具有单一自旋波模式的简单铁磁体。我们使用原子自旋动力学方法来研究全自旋波谱的温度演化，这与中子散射实验在定量上是一致的。由于热泵浦产生的与铁磁模式极化相反的自旋电流，发现反铁磁或光学模式在室温及以上温度会抑制自旋塞贝克效应。
