Optical excitation of single- and multi-mode magnetization precession in Fe-Ga nanolayers

We demonstrate a variety of precessional responses of the magnetization to ultrafast optical excitation in nanolayers of Galfenol (Fe,Ga), which is a ferromagnetic material with large saturation magnetization and enhanced magnetostriction. The particular properties of Galfenol, including cubic magnetic anisotropy and weak damping, allow us to detect up to 6 magnon modes in a 120nm layer, and a single mode with effective damping _eff = 0.005 and frequency up to 100 GHz in a 4- nm layer. This is the highest frequency observed to date in time-resolved experiments with metallic ferromagnets. We predict that detection of magnetisation precession approaching THz frequencies should be possible with Galfenol nanolayers

Noise-induced escape flux on time-scales preceding quasistationarity

Noise-induced escape from the metastable part of potential is considered on time scales preceding the formation of quasiequilibrium within that part of the potential. It is shown that, counterintuitively, the escape flux may depend exponentially strongly, and in a complicated manner, on time and friction

Acoustic phonon generation in a superlattice under the hopping perpendicular transport

Consiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 , Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal