Observation of orbital pumping

Electrons carry both spin and orbital angular momentum. The search for phenomena that generate a flow of spin angular momentum—a spin current—has led to the development of spintronics. In contrast, the orbital counterpart of spin current—an orbital current—has largely been overlooked, and the generation of an orbital current remains challenging. Here we report the observation of orbital-current generation from magnetization dynamics: orbital pumping. We show that orbital pumping in nickel/titanium bilayers injects an orbital current into the titanium layer, which we detect through the inverse orbital Hall effect. Orbital pumping is the orbital counterpart of spin pumping, a versatile and powerful mechanism for spin-current generation. Our findings could, thus, provide a promising approach for generating orbital currents and could help in the development of the orbital analogue of spintronics: orbitronics. In ferromagnetic/non-magnetic bilayers of nickel/titanium, the precession of magnetization in the nickel layer can inject an orbital current into the titanium layer through orbital pumping, the orbital counterpart of spin pumping.