Temperature-dependent study of the spin dynamics of coupled Y3Fe5O12/Gd3Fe5O12/Pt trilayers

Abstract

We combine ferromagnetic resonance absorption measurements (FMR) with spin pumping measurements to ascertain the full magnetization dynamics of Y3⁢Fe5⁢O12 (YIG)/Gd3⁢Fe5⁢O12 (GdIG)/Pt heterostructures. This trilayer system offers the unique possibility to individually investigate the spin dynamics of the ferrimagnetic GdIG close to its compensation temperature. We show that this trilayer acts as a highly tunable spin current source and our experimental results are corroborated by micromagnetic simulations. The detected spin current in the top Pt layer is governed by spin dynamics in the GdIG layer, while the broadband FMR absorption spectrum of the full heterostructure comprises contributions from spin dynamics in both layers. Thus, combining the measurements of FMR absorption and spin current generation from the spin pumping and spin Seebeck effect allows us to understand the spin dynamics contributions of both constituents.