Micromagnetic study of inertial spin waves in ferromagnetic nanodots

Abstract

Here we report the possibility to excite ultra-short spin waves in ferromagnetic thin-films by using time-harmonic electromagnetic fields with terahertz frequency. Such ultra-fast excitation requires to include inertial effects in the description of magnetization dynamics. In this respect, we consider the inertial Landau-Lifshitz-Gilbert (iLLG) equation and develop analytical theory for exchange-dominated inertial spin waves. The theory predicts a finite limit for inertial spin wave propagation velocity, as well as spin wave spatial decay and lifetime as function of material parameters. Then, guided by the theory, we perform numerical micromagnetic simulations that demonstrate the excitation of ultra-short inertial spin waves (20 nm long) propagating at finite speed in a confined magnetic nanodot. The results are in agreement with the theory and provide the order of magnitude of quantities observable in realistic ultra-fast dynamics experiments.

arXiv commentThe following article has been accepted by Physical Review B. After it is published, it will be found at https://journals.aps.org/prb/. Revised version, 9 pages, 6 figures. Changes made in v2: added some references, minor edits and corrections

References in corpus (15)

• All-optical control of ferromagnetic thin films and nanostructures
• The Ultrafast Einstein-De Haas Effect
• Magnetization dynamics in the inertial regime: nutation predicted at short time scales
• Magnetization Dynamics, Gyromagnetic Relation, and Inertial Effects
• Relativistic theory of magnetic inertia in ultrafast spin dynamics
• Spin Dynamics with Inertia in Metallic Ferromagnets
• Inertial spin dynamics in epitaxial cobalt films
• Anatomy of inertial magnons in ferromagnets
• Nonlinear magnetization dynamics driven by strong terahertz fields
• Dispersion relation of nutation surface spin waves in ferromagnets
• Nutation Wave as a Platform for Ultrafast Spin Dynamics in Ferromagnets
• Nutation spin waves in ferromagnets
• Inertial spin waves in ferromagnets and antiferromagnets
• Nutational switching in ferromagnets and antiferromagnets
• Micromagnetic frequency-domain simulation methods for magnonic systems

Cited by in corpus (5)

• Theory of tensorial magnetic inertia in terahertz spin dynamics
• Nonreciprocal inertial spin-wave dynamics in twisted magnetic nanostrips
• Ultrafast Entropy Production in Non-Equilibrium Magnets
• Breather bound states in a parametrically driven magnetic wire
• Optically induced magnetic inertia and magnons from non-Markovian extension of the Landau-Lifshitz-Gilbert equation