Abstract
Recently, bulk spin orbit torques (SOTs) in transition metal-rare earth (TM-RE) ferrimagnets have been reported. In this study, to investigate bulk SOTs, we observed the current-induced effective field mediated by a damping-like torque (DLT), which is one of the components of SOTs, using TM-RE ferrimagnetic Tb
x
(Gd32Fe68)100-x
films with a Ta layer. The DLT efficiency ξ
DL was inactivated by increasing the Tb composition x to be greater than 8, suggesting that the DLT was induced by the bulk SOTs of Tb
x
(Gd32Fe68)100-x
as well as the spin Hall effect in the Ta. However, from the DLT measurement using a Tb8(Gd32Fe68)92 layer sandwiched between Ru layers, where Ru has a negligibly small DLT, ξ
DL was almost zero. This indicates that the inactivation of DLT cannot simply be explained by the bulk SOTs of Tb
x
(Gd32Fe68)100-x
. However, we expect that this finding will provide meaningful insights for controlling magnetization using current.
