Understanding spin currents from magnon dispersion and polarization: Spin-Seebeck effect and neutron scattering study on Tb3Fe5O12

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 Tcomp = 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 Tcomp 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 understanding the magnon spin current.

arXiv comment7 pages, 5 figures

References in corpus (23)

• Enhanced Gilbert Damping in Thin Ferromagnetic Films
• Direct electronic measurement of the spin Hall effect
• Experimental observation of the spin-Hall effect in a two dimensional spin-orbit coupled semiconductor system
• Room Temperature Reversible Spin Hall Effect
• Long distance transport of magnon spin information in a magnetic insulator at room temperature
• Theory of magnon-driven spin Seebeck effect
• Linear spin wave theory for single-Q incommensurate magnetic structures
• Thermally driven spin injection from a ferromagnet into a non-magnetic metal
• Thermoelectric generation based on spin Seebeck effects
• Linear-response theory of spin Seebeck effect in ferromagnetic insulators
• Critical suppression of spin Seebeck effect by magnetic fields
• Thermal spin dynamics of yttrium iron garnet
• The Final Chapter In The Saga Of YIG
• Observation of the Magnon Polarization
• Direct observation of magnon-phonon coupling in yttrium iron garnet
• First-Principles Study of Exchange Interactions of Yttrium Iron Garnet
• Spin Seebeck Effect: Sensitive Probe for Elementary Excitation, Spin Correlation, Transport, Magnetic Order, and Domains in Solids
• Magnon mode selective spin transport in compensated ferrimagnets
• Neutron-scattering study of yttrium iron garnet
• Spincaloritronic measurements: a round robin comparison of the longitudinal spin Seebeck effect
• Neutron Scattering Study on Yttrium Iron Garnet for Spintronics
• A model for coupled $4f-3d$ magnetic spectra: a neutron scattering study of the Yb$-$Fe hybridisation in Yb${}_3$Fe${}_5$O${}_{12}$
• Neutron polarisation correction to triple-axis data with analytical derivations

Cited by in corpus (2)

• Theory of the spin Seebeck effect influenced by crystal-field excitations in Tb${}_3$Fe${}_5$O${}_{12}$
• Anisotropic Band-Split Magnetism in Magnetostrictive CoFe${}_2$O${}_4$