Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

We study the charge and spin dependent scattering in a set of CoFeB thin films whose crystalline order is systematically enhanced and
controlled by annealing at increasingly higher temperatures. Terahertz conductivity measurements reveal that charge transport closely
follows the development of the crystalline phase, with the increasing structural order leading to higher conductivity. The terahertz-induced
ultrafast demagnetization, driven by spin-flip scattering mediated by the spin–orbit interaction, is measurable in the pristine amorphous sam-
ple and much reduced in the sample with the highest crystalline order. Surprisingly, the largest demagnetization is observed at intermediate
annealing temperatures, where the enhancement in spin-flip probability is not associated with an increased charge scattering. We are able to
correlate the demagnetization amplitude with the magnitude of the in-plane magnetic anisotropy, which we characterize independently, sug-
gesting a magnetoresistance-like description of the phenomenon.