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TT: Fachverband Tiefe Temperaturen

TT 17: Magnetic Heuslers, Half-Metals and Oxides (joint session MA, TT, organized by MA)

TT 17.3: Vortrag

Montag, 20. März 2017, 15:30–15:45, HSZ 403

Stability of a highly spin polarized surface resonance of Co₂MnSi at spin-valve interfaces — •Christian Lidig¹, Alexander Kronenberg¹, Andrei Gloskovskii², Mathias Kläui¹, and Martin Jourdan¹ — ¹Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany — ²Deutsches Elektronen-Synchrotron DESY, 22603 Hamburg, Germany

The magnitude of the spin polarization of ferromagnetic materials is a key property for their application in spin transport-based electronics. However it is not the bulk, but the interface of the material, which is relevant for applications. Investigating thin films of Co₂MnSi (CMS) by spin-resolved UPS and spin-integrated HAXPES, we recently observed a high spin polarization at room temperature in a wide energy range below the Fermi energy, which is related to a stable highly spin polarized surface resonance[1,2]. Correspondingly, CMS / Ag / CMS spin valves show large GMR values[3]. However, the use of alternative spacer layers like Cr[4] always resulted in strongly reduced GMR values. A characteristic spectral feature close to the Fermi edge in HAXPES is related to the surface resonance[1]. This spectral feature is completely suppressed at CMS interfaces with Al and Cr and diminished in combination with Cu. However, it is fully conserved at epitaxial interfaces with Ag, explaining the superior magnetoresistance of spin-valves with this materials combination. [1] M. Jourdan et al., Nat. Commun. 5, 3974 (2014). [2] J. Braun et al., Phys. Rev. B 91, 195128 (2015). [3] Y. Sakuraba et al., Appl. Phys. Lett. 101, 252408 (2012). [4] K. Yakushiji et al. Appl. Phys. Lett. 88, 222504 (2006).