Concomitant modulation of interlayer exchange coupling and Gilbert damping in Fe/CoO with spin conductor Ag layer at interface

We report on the modulation of interlayer exchange coupling (IEC) between the ferromagnet (FM) Fe and insulating antiferromagnet (AFM) CoO and its impact on the Gilbert damping by a time-resolved magneto-optical Kerr effect technique. By inserting a wedge spin conductor Ag layer at the interface of Fe/CoO, it is revealed that both uniform spin precession frequency and Gilbert damping constant of Fe film decrease with increasing Ag thickness up to similar to 2 nm, and above that with eliminated IEC, these two parameters reach the intrinsic values of the Fe film. The precession frequency and damping also show similar variation tendency with temperature for attenuated IEC. These results prove that the exchange coupling at the FM-AFM interface plays an essential role for the spin angular momentum transfer to the insulating AFM layer, and the spin pumping is insignificant even for the very thin spin conductor layer. Our findings may have general insights into the role of the FM/AFM interface in the magnetization dynamics and spin angular momentum transfer for future spintronic applications.

Automated summary

We investigate the modulation of interlayer exchange coupling (IEC) between ferromagnet (FM) Fe and insulating antiferromagnet (AFM) CoO and its effect on Gilbert damping using a time-resolved magneto-optical Kerr effect technique. Inserting a wedge spin conductor Ag layer at the Fe/CoO interface reveals that the precession frequency and damping of the Fe film decrease with increasing Ag thickness, reaching intrinsic values above 2 nm where IEC is eliminated. The temperature dependence of the precession frequency and damping also follows a similar trend for attenuated IEC. These findings emphasize the crucial role of exchange coupling at the FM-AFM interface in spin angular momentum transfer and suggest implications for spintronic applications.