Short-Wavelength Spin-Wave Transducer Using the Transmission of Spin-Waves Across Two Magnetic Films

There has been growing interest in using spin waves as an alternative information carrier or state variable. One proposed use of spin waves is to utilize the diffraction and interference of spin waves to perform highly parallelized computing of specific functions. This new class of devices would require isotropic dispersion relations. The subject of this work is a transducer designed to convert electrical signals into short-wavelength forward-volume spin waves. Short-wavelength spin waves would enable spin-wave devices to scale down to smaller sizes and potentially allow the use of films that are CMOS compatible but suffer from higher damping. This work presents a new design of electrical-to-spin-wave transducers that can excite short-wavelength spin waves by first exciting large-wavelength ( $1.43~\mu \text{m}$ for example) spin waves using relatively large coplanar waveguides (CPWs). The spin waves are then transformed into short-wavelength (132 nm) spin waves by traveling into an adjacent film where their wavelengths decrease significantly. Simulations show that this design is able to excite spin waves with significantly larger amplitudes ( $10\times $ ) than an appropriately sized CPW on top of the magnetic film with the same input power.