Electronic structure of fully epitaxial Co₂TiSn thin films

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 degrees C. The films are well ordered in the L2(1) structure, and the Curie temperature slightly exceeds 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 mu(B) on the Co atoms, and a small antiparallel Ti moment, in agreement with theoretical expectations. From comparison of x-ray absorption spectra on the Co L-3,L-2 edges, including circular and linear magnetic dichroism, with ab initio calculations of the x-ray absorption and circular dichroism spectra we infer that the electronic structure of Co2TiSn has essentially nonlocalized character. Spectral features that have not been explained in detail before are explained here in terms of the final-state band structure