Berlin 2018 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 5: Heusler compounds, semimetals and oxides (joint session MA/TT)

MA 5.9: Vortrag

Montag, 12. März 2018, 11:45–12:00, EB 301

NMR investigations of irradiation-induced structural changes in Co₂MnSi thin films — •Franziska Hammerath¹, Mira R. D. Brandt¹, Rantej Bali², Kay Potzger², Roman Böttger², Rene Hübner², Yuya Sakuraba³, Bernd Büchner¹, and Sabine Wurmehl¹ — ¹IFW Dresden, Institute for Solid State Research, Helmholtzstraße 20, 01069 Dresden — ²Institute of Ion Beam Physics and Materials Research, HZDR, Bautzner Straße 400, 01328 Dresden, Germany — ³National Institute for Materials Science (NIMS), Sengen 1-2-1, Tsukuba, Ibaraki 305-0047, Japan

Co₂MnSi is a well-known Heusler compound which is predicted to be half-metallic, i.e., possessing 100% spin-polarization and, thus, being a promising candidate material for enhancing the magneto-resistance of spin-valves [1]. Half-metallicity depends sensitively on the local chemical order, hence methods to improve the structure of Co₂MnSi towards the ideal L2₁ order and, thus, to achieve full spin-polarization are of huge technological relevance. On the basis of XRD measurements it has been argued that irradiation with He⁺ ions induces an improvement of B2-order in Co₂MnSi thin films towards a possible formation of L2₁ order [2]. We investigated the structure-property relationship of He⁺-irradiated Co₂MnSi alloy thin films locally by means of ⁵⁹Co nuclear magnetic resonance (NMR) and observed an increased disorder upon increasing the ion flux, going along with a decrease of the saturation magnetization.

[1] T. Iwase et al., Appl. Phys. Express 2, 063003 (2009).

[2] O. Gaier et al., Appl. Phys. Lett. 94, 152508 (2009).