Abstract: Ferromagnetism in undoped and cobalt-doped high-k HfO2 films was investigated. No ferromagnetism was observed in stoichiometric HfO2 films, but we observed weak ferromagnetism in highly oxygen-deficient HfO2 films. Undoped and cobalt doped films were treated by alternate annealing in vacuum and oxygen atmospheres. From the experiments, both the lack of oxygen vacancies and the increase of oxygen species in bulk (e.g. interstitial oxygen) will degrade the magnetic ordering. Additionally, it is believed that cobalt doping has no obvious relationship with the observed intrinsic d0 magnetism.

Key words: sputtering,  dielectrics,  high k,  d0