[20p-E216-8~20] 10.2 Fundamental and exploratory device technologies for spin

▲ [20p-E216-15] Strong spin Seebeck suppression in a nearly compensated ferrimagnet

〇(PC)Rafael Ramos¹, Tomosato Hioki², Takashi Kikkawa^1,2, Yusuke Hashimoto¹, Eiji Saitoh^1,2,3,4,5 (1.AIMR, Tohoku University, 2.IMR, Tohoku University, 3.Center for Spintronics Research Network, Tohoku University, 4.ASRC, JAEA, 5.Department of Applied Physics, University of Tokyo)

Keywords:Spin caloritronics, Spin Seebeck effect

The spin Seebeck effect (SSE) refers to the generation of a spin current in magnetic materials by the application of a thermal gradient. This spin current generates an electric voltage in a non-magnetic metal attached to the magnet via the inverse spin Hall effect. The SSE can be suppressed by strong magnetic fields as a result of an energy shift in the magnon dispersion induced by the Zeeman effect. This has been previously reported in thick YIG films [1-3].
In this talk, I will report the detection of a strong SSE suppression in a nearly compensated ferrimagnetic iron garnet. The effects is more than three times stronger than in YIG at room temperature and can be possibly understood by the detail of the magnon dispersion in the nearly-compensated ferrimagnet [4], where the contribution of opposite helicity magnons to the SSE can be larger due to a reduced spin wave gap. These results demonstrate the capability of the SSE as an efficient tool to study the spin dynamics in magnetic systems.

[1] T. Kikkawa et al. Phys. Rev. B. 92, 064413 (2015).
[2] H. Jin, et al. Phys. Rev. B 92, 054436 (2015).
[3] U. Ritzmann et al. Phys. Rev. B 92, 174411 (2015).
[4] R. Ramos et al. arXiv:1903.09007 (2019).