Electronic structure of fully epitaxial Co2TiSn thin films

TL;DR

This study investigates the epitaxial growth, magnetic properties, and electronic structure of Co2TiSn thin films, revealing their well-ordered structure, magnetic behavior, and non-localized electronic states through experimental and theoretical analysis.

Contribution

It provides a comprehensive analysis of epitaxial Co2TiSn thin films, combining experimental characterization with ab initio calculations to elucidate their electronic and magnetic properties.

Findings

Films are fully epitaxial and well ordered in L21 structure.

Curie temperature exceeds bulk value.

Electronic structure is essentially non-localized.

Abstract

In this article 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{\deg}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 \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 L3/L2 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 non-localized character. Spectral features that have not been explained in detail before, are explained here in terms of the final state band structure.