Spin dynamics in point contacts to single ferromagnetic films
arXiv:0806.3805 · doi:10.1103/PhysRevB.79.092419
Abstract
Excitation of magnons or spin-waves driven by nominally unpolarized transport currents in point contacts of normal and ferromagnetic metals is probed by irradiating the contacts with microwaves. Two characteristic dynamic effects are observed: a rectification of off-resonance microwave current by spin-wave nonlinearities in the point contact conductance, and a resonant stimulation of spin-wave modes in the nano-contact core by the microwave field. These observations provide a direct evidence that the magnetoconductance effects observed are due to GHz spin dynamics at the ferromagnetic interface driven by the spin transfer torque effect of the transport current.