Kondo effect and impurity band conduction in Co:TiO2 magnetic semiconductor

Abstract

The nature of charge carriers and their interaction with local magnetic moments in an oxide magnetic semiconductor is established. For cobalt-doped anatase TiO2 films, we demonstrate conduction in a metallic donor-impurity band. Moreover, we observe a clear signature of the Kondo effect in electrical transport data with remarkably high Kondo temperatures of up to 120 K. This indicates a strong coupling between local Co moments and delocalized electrons in the impurity band