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MA: Fachverband Magnetismus
MA 14: General Spintronics
MA 14.4: Vortrag
Montag, 16. März 2020, 15:45–16:00, HSZ 401
Spin transport phenomena in vertical spin valves with spacer layers consisting of layered tetragonal FeGe2 — •Dietmar Czubak, Samuel Gaucher, Jens Herfort, Holger Grahn, and Manfred Ramsteiner — Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany
The formation of FeGe2 in a layered tetragonal structure has been recently achieved by solid-phase epitaxy of Ge on Fe3Si. This thin polymorphic film of FeGe2 does not exist in bulk form and appears to be a promising material for spintronic applications. We investigate vertical spin valve structures, in which FeGe2 serves as a spacer layer between the two ferromagnetic Heusler alloy films Fe3Si and Co2FeSi. The spin valves exhibit magnetoresistances up to 0.3%, originating from the switching between parallel and antiparallel magnetization orientations of the ferromagnetic electrodes. This spin valve effect becomes larger with increasing thickness of the spacer layer, which can be explained by a non-dissipative tunneling process dominating the transport through the FeGe2 spacer layer. Additionally, we observe inverted spin valve-like signals by rotating the in-plane direction of the external magnetic field, which are attributed to a tunneling anisotropic magnetoresistance (TAMR). With decreasing temperature, both, the spin valve and the TAMR signals, become smaller and exhibit a correlation with a ferromagnetic phase transition in the FeGe2 layer. These results constitute a crucial step towards the understanding of the fundamental properties of layered FeGe2 films.