Magnetization dynamics of antiferromagnetic metals of PtMn and IrMn driven by a pulsed spin-transfer torque

Abstract

Antiferromagnets are promising materials for memory devices owing to their ultrafast spin dynamics. For efficient control of antiferromagnets, a direct interaction between the spin current and local magnetization of the sublattice is required. In this study, we demonstrated that a short-pulsed spin current can induce fast dynamics of metallic antiferromagnets of PtMn and IrMn via spin-transfer torque on the magnetization of sublattices. We employed two methods to generate a short-pulsed spin current, namely ultrafast demagnetization of a ferromagnet and optical spin polarization of a heavy metal. The magnetization dynamics were measured using the time-resolved magneto-optical Kerr effect and were analyzed using the Landau-Lifshitz-Gilbert equation. Our results provide important evidence of the direct interaction between the magnetization of antiferromagnets and spin current.