Tuning Magnetization Dynamics with Strong Spin-Orbit Coupling in Transition-Metal Dichalcogenide/Co-Fe-B Heterostructures

Spintronic materials with two-dimensional (2D) transition-metal dichalcogenide (TMD)/ferromagnet (FM) interfaces have received a great deal of interest recently due to strong modulation of the magnetic properties, which provide attractive opportunities for magnetic information storage. Here, we demonstrate the strong spin-orbit coupling (SOC) effect and great interfacial tuning of magnetization dynamics in MX2/Co-Fe-B thin films by means of a time-resolved magneto-optical Kerr approach, where M is chosen as Mo or W and X is S or Se. The significant drop of demagnetization time, tau(m), and increase of magnetic damping factor, alpha(s), clearly highlight the presence of high interfacial SOC strength in just one monolayer of MoS2. Compared with the single Co-Fe-B film, the precession frequency, f, is lowered after inserting a MX2 layer, suggesting a reduction of the effective magnetization, 4 pi M-eff, originating from the interfacial d-d hybridization effect. The role of SOC strength on tau(m), M-eff, and alpha(s) is confirmed by using different TMD materials, and thus, demonstrates that the element M plays a dominant role. The samples with WS2 or WSe2 have much shorter tau(m), smaller M-eff, and larger alpha(s) values due to the strong SOC interaction of heavier atoms. The observed efficient control of dynamic magnetic behavior will further promote the development of TMD/FM materials for practical spintronic applications with ultrafast manipulation speed and low energy consumption.