Route toward high-speed nano-magnonics

Downscaling poses a number of new challenges for the implementation of magnonic devices. In particular, the traditional inductive method for spin wave excitation becomes inefficient at nanoscale due to the increasing requirements for the power density, the unavoidable limitations imposed on the wavelength of the excited waves by the geometry of the inductive antennae, and the difficulty of the impedance matching of the latter. An alternative approach to the excitation of spin waves can be based on the spin-transfer torque (STT) mechanism, which provides the ability to directly convert dc electrical currents into microwave-frequency spin waves on nanoscale.