Short-range Thermal Magnon Diffusion in Magnetic Garnet

Abstract

Using the spin Seebeck effect (SSE), we study the propagation distance of thermal spin currents inside a magnetic insulator thin film in the short-range regime. We disambiguate spin currents driven by temperature and chemical potential gradients by comparing the SSE signal before and after adding a thermalization capping layer on the same device. We report that the measured spin decay behavior near the heat source is well accounted for by a diffusion model where the magnon diffusion length is in submicron range, \textit{i.e.} two orders of magnitude smaller than previous estimates inferred from the long-range behavior. Our results highlight the caveat in applying a diffusive theory to describe thermal magnon transport, where a single decay length may not capture the behavior on all length scales.

References in corpus (10)

• Theory of spin Hall magnetoresistance
• Theory of magnon-driven spin Seebeck effect
• Thermal spin dynamics of yttrium iron garnet
• Quantitative Temperature Dependence of Longitudinal Spin Seebeck Effect at High Temperatures
• Interfacial Spin and Heat Transfer between Metals and Magnetic Insulators
• Influence of yttrium iron garnet thickness and heater opacity on the nonlocal transport of electrically and thermally excited magnons
• Criteria for accurate determination of the magnon relaxation length from the nonlocal spin Seebeck effect
• Thermally Driven Long Range Magnon Spin Currents in Yttrium Iron Garnet due to Intrinsic Spin Seebeck Effect
• Lateral transport properties of thermally excited magnons in yttrium iron garnet films
• Enhancement of YIG$|$Pt spin conductance by local Joule annealing

Cited by in corpus (5)

• Spin Seebeck Effect: Sensitive Probe for Elementary Excitation, Spin Correlation, Transport, Magnetic Order, and Domains in Solids
• Bright and dark states of two distant macrospins strongly coupled by phonons
• Non-local magnon transconductance in extended magnetic insulating films.\\ Part I: spin diode effect
• Non-local magnon transconductance in extended magnetic insulating films.\\Part II: two-fluid behavior
• Magnonic spin Joule heating and rectification effects