Phys.org October 18, 2021
Magnetic solids can be demagnetized quickly with a short laser pulse. However, the microscopic mechanisms of ultrafast demagnetization remain unclear. Researchers in Germany have developed a method to quantify the temperature-dependent electron–phonon scattering rate in gadolinium measuring independently the electron-phonon scattering rate for the 5d and the 4f electrons. They deduced the temperature dependence of scattering for the 5d electrons, while no effect on the phonon population is observed for the 4f electrons. The results suggest that the ultrafast magnetization dynamics in Gd is triggered by the spin-flip in the 5d electrons, found evidence of the existence of a temperature threshold, above which spin-flip scattering of the 5d electrons takes place and that during the transient state of ultrafast demagnetization, the exchange energy between 5d electrons must be overcome before the microscopic electron-phonon scattering process can occur. Understanding these mechanisms is useful for developing ultrafast data storage devices…read more. Open Access TECHNICAL ARTICLE  1 , 2 , 3
Schematic principle of the XES process in the presence or absence of spin-flip scattering in nickel after the creation of a core-hole… Credit: Scientific Reports volume 9, Article number: 8977 (2019)Â