The functionality for a range of complex metal oxides is controlled by the interplay between lattice, spin, charge, and orbital degrees of freedom. Experimentally, it has been demonstrated that the oxygen content is one of the key parameters in controlling this interplay and thus significantly influence the physical properties; for example, Mn-O-Mn chains in manganite perovskite oxides determine the ferromagnetism and magnetotransport properties12. In semiconducting oxides, oxygen vacancies usually serve as dopants (since the energy level is above the middle of the bandgap) and impact the electrical behavior. Because the oxygen content in complex metal oxides allows the manipulation of desired physical properties345678, it is a crucial aspect of consideration in the design, synthesis, and application of functional oxide thin films. In perovskite oxides with ABO3 structure, oxygen content-driven A-site and B-site vacancies have been reported to significantly alter the physical properties of thin films. There have been tremendous efforts to understand the effect of changes in oxygen content on the properties of perovskite thin films that are not composed of cations with multiple valance states. While oxygen vacancies have been recently been reported to act as desired defects91011121314151617, the oxygen content effect in perovskite compounds with multiple valance states at the B site can provide a deeper understanding of the underlying mechanics of the functional properties observed in these materials18.