ﻻ يوجد ملخص باللغة العربية
By means of time-resolved Kerr spectroscopy experiments we relate the energy dissipation processes on the femtosecond (electron-spin relaxation time $tau_{el-sp}$) and nanosecond timescale (Gilbert relaxation $tau_{alpha}$) and compare the results to the first microscopic model, which was proposed by Koopmans. For both energy dissipation processes, Elliot-Yafet scattering is proposed as the dominant contributor. We controllably manipulate the energy dissipation processes by transition metal doping (Pd) and rare earth doping (Dy) of a Permalloy film and find that while a change of $tau_{alpha}$ of more than a factor two is observed, tau_{el-sp}$ remains constant, contrary to the predictions of the model. We explain the discrepancies by relaxation channels not considered in the original microscopic model and identify thereby the applicability of the model and possible necessary extensions to the model.
The phonon density of states (DOS) and magnetic excitation spectrum of polycrystalline BiFeO$_3$ were measured for temperatures $200 leq T leq 750,$K, using inelastic neutron scattering (INS). Our results indicate that the magnetic spectrum of BiFeO$
First-principles calculations combining density functional theory and many-body perturbation theory can provide microscopic insight into the dynamics of electrons and phonons in materials. We review this theoretical and computational framework, focus
Spin and lattice dynamics of CaMn7O12 ceramics were investigated using infrared, THz and inelastic neutron scattering (INS) spectroscopies in the temperature range 2 to 590 K, and, at low temperatures, in applied magnetic fields of up to 12 T. On coo
The interaction between magnetic and acoustic excitations have recently inspired many interdisciplinary studies ranging from fundamental physics to circuit implementation. Specifically, the exploration of their coherent interconversion enabled via th
We show how to create quantum squeezed states of magnons and phonons in a cavity magnomechanical system. The magnons are embodied by a collective motion of a large number of spins in a macroscopic ferrimagnet, and couple to cavity microwave photons a