Lattice dynamics and ultrafast energy flow between electrons, spins, and phonons in a 3d ferromagnet

Abstract

The ultrafast dynamics of magnetic order in a ferromagnet are governed by the interplay between electronic, magnetic and lattice degrees of freedom. In order to obtain a microscopic understanding of ultrafast demagnetization, information on the response of all three subsystems is required. A consistent description of demagnetization and microscopic energy flow, however, is still missing. Here, we combine a femtosecond electron diffraction study of the ultrafast lattice response of nickel to laser excitation with ab initio calculations of the electron-phonon interaction and energy-conserving atomistic spin dynamics simulations. Our model is in agreement with the observed lattice dynamics and previously reported electron and magnetization dynamics. Our approach reveals that the spin system is the dominating heat sink in the initial few hundreds of femtoseconds and implies a transient non-thermal state of the spins. Our results provide a clear picture of the microscopic energy flow between electronic, magnetic and lattice degrees of freedom on ultrafast timescales and constitute a foundation for theoretical descriptions of demagnetization that are consistent with the dynamics of all three subsystems.

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Cited by in corpus (16)

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• Revealing Non-equilibrium and Relaxation in Warm Dense Matter
• Intrinsic energy flow in laser-excited 3$d$ ferromagnets
• Ultrafast Demagnetization through Femtosecond Generation of Non-thermal Magnons
• Lattice dynamics and phonon dispersion of van der Waals layered ferromagnet Fe3GaTe2
• Energy relaxation and electron-phonon coupling in laser-excited metals
• Ultrafast magnetization reversal in ferromagnetic spin-valves: an s-d model perspective
• Electron-phonon mediated spin-flip as driving mechanism for ultrafast magnetization dynamics in 3$d$ ferromagnets
• Heat-conserving three-temperature model for ultrafast demagnetization of 3d ferromagnets
• Optically- and thermally-driven huge lattice orbital and spin angular momenta from spinning fullerenes
• Spin-phonon dispersion in magnetic materials
• Laser-induced forces on atoms during ultrafast demagnetization
• Hidden-anisotropy-induced $\pi$ phase shift in all-optical magnetization precession
• Electronic mechanism of sub-100-fs demagnetization induced by a femtosecond light pulse
• Mode-Dependent Phonon Relaxation in fcc Ni: Insights from Molecular Dynamics Simulations with Frozen-Trajectory Excitations