Magnetic field dependence of the nonlocal spin Seebeck effect in Pt/YIG/Pt systems at low temperatures

Abstract

We report the nonlocal spin Seebeck effect (nlSSE) in a lateral configuration of Pt/Y 3 Fe 5 O 12 (YIG)/Pt systems as a function of the magnetic field B (up to 10 T) at various temperatures T (3 K < T < 300 K). The nlSSE voltage decreases with increasing B in a linear regime with respect to the input power (the applied charge-current squared I 2 ). The reduction of the nlSSE becomes substantial when the Zeeman energy exceeds thermal energy at low temperatures, which can be interpreted as freeze-out of magnons relevant for the nlSSE. Furthermore, we found the non-linear power dependence of the nlSSE with increasing I at low temperatures (T < 20 K), at which the B-induced signal reduction becomes less visible. Our experimental results suggest that in the non-linear regime high-energy magnons are over populated than those expected from the thermal energy. We also estimate the magnon spin diffusion length as functions of B and T .

Dynamic magnetoelastic boundary conditions and the pumping of phonons

“…We focus here on microwave absorption experiments such as carried out by An et al [16]. However, all experiments sensitive to the magnon polarons in YIG, such as pump and probe spectroscopy [77,78], local and non-local spin Seebeck effect [79,80], and Brillouin light scattering [81] are affected by the phonon pumping into GGG substrates and can in principle test our results.…”

Green's function formalism for nonlocal elliptical magnon transport

“…Here j R→L s0 (T L , T R ) and = j B→L s0 (T L , T B ) are spin Seebeck effect [12,41] terms that vanish when T L = T R and T L = T B , respectively.…”

“…The latter forms a broad field of research known as magnonics [6]. In recent years, significant milestones, both experimental and theoretical, have been achieved in the field of magnonics, with non-local transport of spin through ferromagnetic insulators [7][8][9][10][11][12] now commonly realized and fairly well described using theoretical frameworks that range from drift-diffusion models to non-equilibrium Green's function formalism [13][14][15][16].…”

Triplon current generation in solids

“…The SSE has been observed in various insulating systems, in which parasitic thermal effects originating from itinerant electrons can be eliminated. Some types of spin carriers including magnons in magnets [5][6][7][8] , paramagnons 9 , antiferromagnetic magnons 7,8 , and spinons in a spin liquid 10,11 have been demonstrated for different mechanisms of the SSE.…”

“…Pt systems7 ; the non-linearity is attributed to the strong non-equilibrium excitation of magnons in Y 3 Fe 5 O 12 . Another possibility for the non-linearity in the CuGeO 3 case is temperature rise of the CuGeO 3 sample due to the Joule heating, since V SSE should decrease with increasing T .…”