Microscopic electronic configurations after ultrafast magnetization dynamics

Abstract

We provide a model for the prediction of the electronic and magnetic configurations of ferromagnetic Fe after an ultrafast decrease or increase of magnetization. The model is based on the well-grounded assumption that, after the ultrafast magnetization change, the system achieves a partial thermal equilibrium. With statistical arguments it is possible to show that the magnetic configurations are qualitatively different in the case of reduced or increased magnetization. The predicted magnetic configurations are then used to compute the dielectric response at the 3p (M) absorption edge, which can be related to the changes observed in the experimental T-MOKE data. The good qualitative agreement between theory and experiment offers a substantial support to the existence of an ultrafast increase of magnetisation, which has been fiercely debated in the last years.

Main text 10 pages including 7 figures. Supplemental material 5 pages including 1 figure

References in corpus (6)

• Thermalization and its mechanism for generic isolated quantum systems
• Super-Diffusive Spin-Transport as a Mechanism of Ultrafast Demagnetization
• On the time scales in the approach to equilibrium of macroscopic quantum systems
• Ab initio theory of electron-phonon mediated ultrafast spin relaxation of laser-excited hot electrons in transition-metal ferromagnets
• Influence of laser-excited electron distributions on the x-ray magnetic circular dichroism spectra: Implications for femtosecond demagnetization in Ni
• Pure state thermodynamics with matrix product states

Cited by in corpus (6)

• Ultrafast and gigantic spin injection in semiconductors
• Analysis of the linear relationship between asymmetry and magnetic moment at the M-edge of 3d transition metals
• Distinctive Picosecond Spin Polarization Dynamics in Bulk Half-Metals
• Heat-conserving three-temperature model for ultrafast demagnetization of 3d ferromagnets
• Spin polarisation of ultrashort spin current pulses injected in semiconductors
• Charge pumping driven by the laser-induced dynamics of the exchange splitting