Magnetization Dynamics of Synthetic Antiferromagnets with Perpendicular Magnetic Anisotropy*

Synthetic antiferromagnets with perpendicular magnetic anisotropy (p-SAFs) are appealing for spintronics due to their low stray field, ultra-high switching speed, and compatibility with perpendicular devices offering enhanced scalability. Capturing magnetization dynamics in p-SAFs and revealing the underlying physics are crucial for advancing next-generation spintronic devices. Recently, by combining theoretical modeling and time-resolved magneto-optical Kerr effect (TR-MOKE) measurements, we systematically studied magnetization dynamics in an asymmetric p-SAF featuring two distinct ferromagnetic layers. Utilizing the Landau-Lifshitz-Gilbert equation while accounting for exchange coupling, mutual spin pumping, and inhomogeneities, the theoretical model furnishes a wealth of information, detailing the amplitudes, directions, phase, and damping of magnetization procession in p-SAFs. These insights not only well describe the observed TR-MOKE signals, but also enable us to extract the properties of p-SAFs, such as effective anisotropy field, interlayer exchange coupling, and Gilbert damping. This work provides a comprehensive understanding of the magnetization dynamics in p-SAFs and offers valuable guidance for the design of p-SAF-based spintronic architectures. Towards the conclusion, we will present an example that highlights the advantages of TR-MOKE for characterizing p-SAFs with strong perpendicular magnetic anisotropy and exchange coupling.