Magnetic field modulated ultrafast spin dynamics at NiFe/Neodymium interface.

Ultrafast spin dynamics is crucial for the next-generation spintronic devices towards high-speed data processing. Here, we investigate the ultrafast spin dynamics of Neodymium/NiFe (Nd/Py) bilayers by the time-resolved magneto-optical Kerr effect. The effective modulation of spin dynamics at Nd/Py interfaces is realized by an external magnetic field. The effective magnetic damping of Py increases with increasing Nd thickness, and a large spin mixing conductance (∼19.35×10cm) at Nd/Py interface is obtained, representing the robust spin pumping effect by Nd/Py interface. The tuning effects are suppressed at a high magnetic field due to the reduced antiparallel magnetic moments at Nd/Py interface. Our results contribute to understanding ultrafast spin dynamics and spin transport behavior in high-speed spintronic devices.