Long-range dynamic interaction between insulating ferromagnetic films mediated by phonons
Published : 28 March 2019
The proposed research project inserts itself in the emerging field of insulator spintronics whose vision is to fully replace the moving electrical charge with the friction-free propagation of the spin degree of freedom using electrical insulators. In this novel paradigm, low damping magnetic insulators are good spin-conductors by allowing the long-range propagation of the spin information trough spin-waves. In this project we shall investigate the role of acoustic-waves. The project shall focus on Yttrium Iron Garnet (YIG) thin films grown on Gadolinium Gallium Garnet (GGG) substrate because i) of the strong magneto-elastic constant in YIG, which should allow efficient interconversion of magnetic energy into acoustic; ii) of the small acoustic impedance mismatch between YIG and GGG; and iii) of the ultra-low acoustic damping in garnets (better than quartz). The target here is to study dynamical exchange between magnons and phonons. This will be measured by performing frequency and time-domain spectroscopic studies on YIG thin films prepared by liquid phase epitaxy. We believe that these progresses on hybrid transducers exploiting the magneto-elastic coupling could be beneficial for the development of the future microwave analog front-end technology (e.g. delay lines and filters) used in the wireless industry. The efficiency of this interconversion process could help removing the high frequency limitations of piezo transducers found in acoustic devices.