Oxygen vacancies induced ferromagnetic behaviors in Co3O4–δ: An experimental and first-principles study

Publication date: 30 August 2018
Source:Thin Solid Films, Volume 660
Author(s): P. Wang, C. Jin, P. Li, D.X. Zheng, J.L. Gong, H.L. Bai
The structural and magnetic properties of Co3O4–δ were investigated by both first-principles and experimental studies. The results of first-principles calculations indicate that the spin splitting induced by oxygen vacancies can lead to the net moment in the Co3O3.875. The density of states of Co3O4 shows a band gap of 2.2 eV, while the impurity states appear with the oxygen vacancies. Furthermore, the Co3O4–δ films with oxygen vacancies were grown on MgAl2O4 and SrTiO3 substrates by using reactive sputtering. The structural analysis reveals that the Co3O4–δ films are epitaxial. Consistent with the first-principles study, magnetism is observed in the Co3O4–δ films, which attributes to the oxygen vacancies influencing spin structure by superexchange interaction.