Dresden 2011 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 52: Magnetic Thin Films III

MA 52.1: Vortrag

Donnerstag, 17. März 2011, 11:00–11:15, HSZ 403

Electronic structure of fully epitaxial Co2TiSn thin films — •Markus Meinert¹, Jan-Michael Schmalhorst¹, Hendrik Wulfmeier¹, Günter Reiss¹, Elke Arenholz², Tanja Graf³, and Claudia Felser³ — ¹Dünne Schichten und Physik der Nanostrukturen, Fakultät für Physik, Universität Bielefeld, 33501 Bielefeld, Deutschland — ²Advanced Light Source, Lawrence Berkeley National Laboratory, CA 94720, USA — ³Institut für Anorganische Chemie und Analytische Chemie, Johannes-Gutenberg-Universität, 55128 Mainz, Deutschland

We report on the properties of thin films of the full Heusler compound Co2TiSn prepared by DC magnetron co-sputtering. Fully epitaxial, stoichiometric films were obtained by deposition on MgO (001) substrates at substrate temperatures above 600^∘C. The films are well ordered in the L2₁ structure, and the Curie temperature exceeds slightly the bulk value. They show a significant, isotropic magnetoresistance and the resistivity becomes strongly anomalous in the paramagnetic state. The films are weakly ferrimagnetic, with nearly 1 µ_B on the Co atoms, and a small antiparallel Ti moment, in agreement with theoretical expectations. X-ray absorption spectra on the Co L_3,2 edges, including circular and linear magnetic dichroism are compared with ab initio calculations of the x-ray absorption and circular dichroism spectra. We infer that the electronic structure of Co2TiSn has essentially non-localized character. Spectral features that have not been explained in detail before, are explained here in terms of the final state band structure.