Nonlocal Uniform-Mode Ferromagnetic Resonance Spin Pumping*

Nonlocal spin transport using lateral structures is attractive for spintronic devices. Typically, a spin current is generated by a ferromagnetic (FM) or a heavy metal (HM) electrode in a nonlocal structure, which can be detected by another FM or HM electrode. Here, we report a new nonlocal spin injection scheme using uniform-mode ferromagnetic resonance (FMR) spin pumping in Pt/ Y3Fe5O12 (YIG) lateral structures. This scheme is enabled by well separated resonant fields of Pt/YIG and bare YIG due to substantial change of anisotropy in YIG films induced by a Pt overlayer, allowing for clearly distinguishable local and nonlocal spin pumping. Our results show that the spin decay length of nonlocal uniform-mode spin pumping in 20 nm YIG films is 2.1 μm at room temperature. The first observation of the nonlocal spin pumping through high efficiency angular momentum transfer from the uniform FMR mode in a resonant region into a nonresonant region opens up a new path for spin current generation, propagation, and detection in future spintronic applications.