Insights to spin transport–driven ultrafast magnetization dynamics - TRR 227 results published in Science Advances
Ultrafast spin transport in a ferrimagnetic Gd/Fe bilayer after femtosecond excitation probed by time- and spin-resolved photoemission of the Gd surface state, © Science Advances
TRR 227 PI Martin Weinelt (project A01) and coworkers published their latest work on ultrafast magnetization dynamics in the journal "Science Advances". Using time- and spin-resolved photoemission spectroscopy, the researchers studied an antiferromagnetically coupled Gd/Fe bilayer, a prototype system for all-optical switching. Spin transport leads to an ultrafast drop of the spin polarization at the Gd surface, demonstrating angular-momentum transfer over several nanometers.
News from May 23, 2023
The findings show that Fe acts as spin filter, absorbing spin majority but reflecting spin minority electrons. Spin transport from Gd to Fe was corroborated by an ultrafast increase of the Fe spin polarization in a reversed Fe/Gd bilayer. In contrast, for a pure Gd film, spin transport into the tungsten substrate can be neglected, as spin polarization stays constant.
The reported results provide clear evidence that magnetization dynamics in the Gd/Fe bilayer can be driven by spin transport. Distinct signatures in the spin-dependent electronic structure are observed that allow to gain microscopic insights into ultrafast spin dynamics. These findings are of general importance for the understanding of magnetization switching in ferrimagnetic Gd-Fe compounds.
B. Liu, H. Xiao, and M. Weinelt: Microscopic insights to spin transport–driven ultrafast magnetization dynamics in a Gd/Fe bilayer - Sci. Adv. 9: eade0286 (2023) - DOI: 10.1126/sciadv.ade0286