Spin waves in coupled YIG/Co heterostructures

TL;DR

This study explores the interaction of spin waves in YIG/Co heterostructures, revealing efficient excitation of standing spin waves and their coupling mechanisms, with implications for magnonic device engineering.

Contribution

It demonstrates the excitation and coupling of perpendicular standing spin waves in YIG/Co heterostructures, introducing a model involving mutual spin pumping and exchange torques.

Findings

Efficient excitation of YIG PSSWs at resonance with Co FMR.

Avoided crossings indicating strong coupling between YIG PSSWs and Co FMR.

Interlayer materials influence PSSW excitation, with AlOx suppressing it.

Abstract

We investigate yttrium iron garnet (YIG)/cobalt (Co) heterostructures using broadband ferromagnetic resonance (FMR). We observe an efficient excitation of perpendicular standing spin waves (PSSWs) in the YIG layer when the resonance frequencies of the YIG PSSWs and the Co FMR line coincide. Avoided crossings of YIG PSSWs and the Co FMR line are found and modeled using mutual spin pumping and exchange torques. The excitation of PSSWs is suppressed by a thin aluminum oxide (AlOx) interlayer but persists with a copper (Cu) interlayer, in agreement with the proposed model.