• Lee, S.E.; Windsor, Y.W.; Zahn, D.; Kraiker, A.; Kummer, K.; Kliemt, K.; Krellner, C.; Schüßler-Langeheine, C.; Pontius, N.; Staub, U.; Vyalikh, D.V.; Ernst, A.; Rettig, L.: Controlling 4f antiferromagnetic dynamics via itinerant electronic susceptibility. Physical Review Research 6 (2024), p. 043019/1-9

10.1103/physrevresearch.6.043019
Open Access Version

Abstract:
Optical manipulation of magnetism holds promise for future ultrafast spintronics, especially with lanthanides and their huge, localized 4⁢𝑓 magnetic moments. These 4f moments interact indirectly by spin polarizing the conduction electrons (the Ruderman-Kittel-Kasuya-Yosida exchange interaction), influenced by interatomic orbital overlap, and the conduction electron's susceptibility around the Fermi level. Here, we study this influence in a series of 4⁢𝑓 antiferromagnets, Gd⁢𝑇2⁢Si2 (𝑇 = Co, Rh, Ir), using ultrafast resonant x-ray diffraction. We observe a twofold increase in the ultrafast intersublattice angular momentum transfer rate between the materials, originating from modifications in the conduction electron susceptibility, as confirmed by first-principles calculations.