Magneto-mechanical investigation of spin dynamics in magnetic multilayers

The Einstein-de Haas effect is used to study experimentally the interfacial spin transport in a bilayer metallic system. Specifically, mechanical torque on a permalloy film interfaced with a non-magnetic metallic film (platinum or copper), deposited on a microcantilever, is measured. The torque is generated by the transfer of the spin angular momentum from the permalloy film to the mechanical angular momentum of the cantilever. Measurement of the cantilever deflection shows that the presence of a thin non-magnetic metallic layer with strong spin-orbit interaction (platinum) changes the interfacial spin transport and causes a dramatic reduction of the mechanical torque. The observed behavior of the cantilever is attributed to the increased effective damping of the domain wall motion in the permalloy layer.