salle 22-32-201
Pietro Carrara, post-doctorant dans l’équipe Nanostructures: élaboration, effets quantiques et magnétisme
Abstract
Hybrid quasi-particles in condensed matter systems are observed at the degeneracy points between different degrees of freedom exhibiting non-zero coupling. These solid-state chimeras could be exploited in a wealth of applications, ranging from transducers to sensors, to memory and logic units. In particular, when the dispersion relation of phonons and of magnons are degenerate, magnetostriction can allow for efficient cross-talk between lattice and spin reservoirs in the few gigahertz range. Notably, such degeneracy can take place at finite wavevector: suitable experimental methods to investigate the dispersion relation in the vicinity of the mode crossing are called for.
I will present results from my Ph.D. activity on finite-wavevector magneto-acoustics in ferromagnetic thin film and nanostructures. The systems have been investigated via optical Transient-Grating (TG) spectroscopy and time-resolved MOKE at NFFA-SPRINT laboratory (Trieste); correlative characterization of the samples further confirm the observed dynamics and allow to draw the boundary for reliable data interpretation. Hamiltonian modelling of the mode crossing allows to quantify the magnon-phonon coupling strength and the degree of coherence in the coupling.
