Microwave-induced spin currents in ferromagnetic-insulator|normal-metal bilayer system

TL;DR

This study uses microwave techniques to investigate spin currents in a YIG|Pt bilayer, revealing opposite flow directions for spin pumping and spin Seebeck effects and highlighting the role of thermal-magnon diffusion.

Contribution

It introduces a microwave-based method to simultaneously analyze spin pumping and spin Seebeck effects in a bilayer system, demonstrating their opposite spin current directions.

Findings

Spin current flows in opposite directions for the two effects.

The spin Seebeck effect depends on thermal-magnon diffusion.

Microwave techniques enable simultaneous examination of spin phenomena.

Abstract

A microwave technique is employed to simultaneously examine the spin pumping and the spin Seebeck effect processes in a YIG|Pt bilayer system. The experimental results show that for these two processes, the spin current flows in opposite directions. The temporal dynamics of the longitudinal spin Seebeck effect exhibits that the effect depends on the diffusion of bulk thermal-magnons in the thermal gradient in the ferromagnetic-insulator|normal-metal system.