Tuneable power-phase distributions in phonon-magnon coupled nano-patterned heterostructures: Magnon Microwave Antenna for reservoir computing

Exploring the power and phase profiles of spin waves not only enhances our fundamental understanding of magnetic materials but also opens up avenues for innovative applications in energy-efficient technologies such as, spintronics, magnonics, and reservoir computing. Here, we present the power-phase distributions and their tuneability of a surface acoustic wave (SAW) driven nano-patterned “Magnon Microwave Antenna” (MMA), comprised of patterned arrays of magnetostrictive nanomagnets embedded in piezoelectric heterostructures. The MMA generates tunable microwave frequencies without any external bias magnetic fields. The phonon-magnon coupling within the patterned array of nanowires and nanodots generates a multimode microwave frequencies with nonvolatile spin textures in both configurations. A comprehensive static magnetic study elucidates various magnetization reversal process within the nanowires/nanodot arrays. The investigation unveils the crucial role of the demagnetization energy distribution (strength of the dipolar magnetic field) rather than its overall magnitude. Additionally, the external bias magnetic field conditions offer the possibility of tuning the domain configuration vis-à-vis power-phase distributions of these MMAs. Notably, the non-volatile nature of the spin textures generated out of the nanowires/nanodots in the MMA, under bias-field free condition is promising for energy-efficient logic and low-power computing applications. Furthermore, given that MMA consists of piezoelectric/magnetostrictive heterostructures, this work introduces a novel alternative approach, paving the way to utilize these MMAs for on-chip reservoir computing, where amplitude varies at the operating frequency.