Abstract
Magnon spin currents in the ferrimagnetic garnet Tb3Fe5O12 with 4f electrons were examined through the spin-Seebeck effect and neutron scattering measurements. The compound shows a magnetic compensation, where the spin-Seebeck signal reverses above and below T comp = 249.5 ( 4 ) K. Unpolarized neutron scattering unveils two major magnon branches with finite energy gaps, which are well explained in the framework of spin-wave theory. Their temperature dependencies and the direction of the precession motion of magnetic moments, i.e., magnon polarization, defined using polarized neutrons, explain the reversal at T comp and decay of the spin-Seebeck signals at low temperatures. We illustrate an example that momentum- and energy-resolved microscopic information is a prerequisite to understand the magnon spin current.
| Original language | English |
|---|---|
| Article number | 132406 |
| Journal | Applied Physics Letters |
| Volume | 124 |
| Issue number | 13 |
| DOIs | |
| State | Published - Mar 25 2024 |
| Externally published | Yes |
Funding
We thank J. Barker, G. E. W. Bauer, Y. Ikeda, M. Mori, J. Nasu, Y. Onose, and T. J. Sato for valuable discussions. This work was supported by the JSPS (Nos. 21H03732, 22H05145, 19K21031, 19H05600, 22K18686, and 22H05114), ERATO “Spin Quantum Rectification Project” (No. JPMJER1402), CREST (Nos. JPMJCR20C1 and JPMJCR20T2), and FOREST (No. JPMJFR202V) from JST, Institute for AI and Beyond of the University of Tokyo, and Collaborative Research Center on Energy Materials at Institute for Materials Research, Tohoku University. 4SEASONS experiment was carried out through the Proposal No. 2018B0207. Work at ANSTO was supported by the Graduate Program in Spintronics at Tohoku University.