Direct observation of half-metallicity in the Heusler compound Co2MnSi

作者：Jourdan, M.^*; Minar, J.; Braun, J.; Kronenberg, A.; Chadov, S.; Balke, B.; Gloskovskii, A.; Kolbe, M.; Elmers, H. J.; Schoenhense, G.; Ebert, H.; Felser, C.; Klaeui, M.

来源：Nature Communications, 2014, 5(1): 3974.

DOI：10.1038/ncomms4974

• PHOTOELECTRON-SPECTROSCOPY
• ALLOYS

Ferromagnetic thin films of Heusler compounds are highly relevant for spintronic applications owing to their predicted half-metallicity, that is, 100% spin polarization at the Fermi energy. However, experimental evidence for this property is scarce. Here we investigate epitaxial thin films of the compound Co2MnSi in situ by ultraviolet-photoemission spectroscopy, taking advantage of a novel multi-channel spin filter. By this surface sensitive method, an exceptionally large spin polarization of (93(-11)(+7)) % at room temperature is observed directly. As a more bulk sensitive method, additional ex situ spin-integrated high energy X-ray photoemission spectroscopy experiments are performed. All experimental results are compared with advanced band structure and photoemission calculations which include surface effects. Excellent agreement is obtained with calculations, which show a highly spin polarized bulk-like surface resonance ingrained in a half metallic bulk band structure.

• 出版日期2014-5