Dresden 2017 – wissenschaftliches Programm
MA 15.3: 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. However, the use of alternative spacer layers like Cr always resulted in strongly reduced GMR values. A characteristic spectral feature close to the Fermi edge in HAXPES is related to the surface resonance. 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.  M. Jourdan et al., Nat. Commun. 5, 3974 (2014).  J. Braun et al., Phys. Rev. B 91, 195128 (2015).  Y. Sakuraba et al., Appl. Phys. Lett. 101, 252408 (2012).  K. Yakushiji et al. Appl. Phys. Lett. 88, 222504 (2006).