2018年第79回応用物理学会秋季学術講演会

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10 スピントロニクス・マグネティクス » 10.2 スピン基盤技術・萌芽的デバイス技術

[19a-331-1~6] 10.2 スピン基盤技術・萌芽的デバイス技術

2018年9月19日(水) 09:00 〜 10:30 331 (国際会議室)

飯浜 賢志(東北大)

10:00 〜 10:15

[19a-331-5] Spin Seebeck detection of magnon-polaron excitations in a nonmagnetic-ion-substituted garnet system

Rafael Ramos1、Tomosato Hioki2、Takashi Kikkawa1,2、Yusuke Hashimoto1、Eiji Saitoh1,2,3,4,5 (1.AIMR Tohoku Univ.、2.IMR Tohoku Univ.、3.CSNR Tohoku Univ.、4.ASRC JAEA、5.Dep. Appl. Phys. Tokyo Univ.)

キーワード:Spin caloritronics, Spin Seebeck effect, Magnon-phonon interaction

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.
Recently, the effect of magnon-phonon hybridization, resulting from the crossing of the magnon and phonon dispersions, has been detected by SSE measurement in Ytrium Iron Garnet (YIG). This is experimentally observed as spikes of the SSE-voltage at the magnetic field values for which the magnon-phonon hybridization is maximized over k-space [1-3].
In this talk, we report the detection of magnon-phonon hybridization in a nonmagnetic-ion-substituted garnet system by means of the SSE. The magnon dispersion can be strongly affected by the nonmagnetic-ion substitutions, thus resulting in a clear modification of the magnetic field condition for the observation of magnon-polarons, with respect to the case of non-substituted YIG. The results demonstrate the SSE as an efficient tool to study the magnon-phonon coupled dynamics in magnetic systems.

[1] T. Kikkawa et al. Phys. Rev. Lett. 117, 207203 (2016).
[2] B. Flebus, et al. Phys. Rev. B 95, 144420 (2017).
[3] L. J. Coernelissen et al. Phys. Rev. B 96, 104441 (2017).