First-principles study of electronic structure and magnetic properties of Cu-doped CeO2

We performed first-principles calculations within density-functional theory to study the origin of the magnetism in Cu-doped CeO2. We show that the electron spin-polarization and the magnetic coupling are sensitive to the defect structures in Cu-doped CeO2. The substitution of a Cu atom for a Ce atom (CuCe) induces a local magnetic moment of 3.00 μB around per impurity, but the magnetic coupling between local magnetic moments is very weak. The defect complex consisting of a CuCe and a nearest-neighbor oxygen vacancy (VO) has low formation energy and thus high plausibility in Cu-doped CeO2. Although the local magnetic moment triggered by the CuCe-VO complex is only 1.00 μB per complex, strong ferromagnetic coupling between the defect complexes is achieved which can be attributed to a magnetic coupling chain formed by the strong p-d interaction between Cu and host O atoms.