Oxygen-vacancy-induced ferromagnetism in CeO2 from first principles

The electronic and magnetic properties of CeO2 with various concentrations of oxygen vacancies have been studied by first-principles calculations within the LSDA+U method and were found to remarkably depend on the oxygen vacancy concentration. With increasing oxygen deficiency, the electrons left behind by oxygen removal not only localize on Ce 4f orbitals but also on the vacancy sites. This leads to the magnetic mechanism with both superexchange and polarization in the cases of heavy doping, effectively enhancing the stability of ferromagnetism. The study reveals the magnetic properties and associated magnetic mechanisms of CeO2 with the different oxygen deficiencies.