Oxygen content tailored magnetic and electronic properties in cobaltite double perovskite thin films

Oxygen content in transition metal oxides is one of the most important parameters to control for the desired physical properties. Recently, we have systematically studied the oxygen content and property relationship of the double perovskite PrBaCo₂O_5.5+δ (PBCO) thin films deposited on the LaAlO₃ substrates. The oxygen content in the films was varied by in-situ annealing in a nitrogen, oxygen, or ozone environment. Associated with the oxygen content, the out-of-plane lattice parameter progressively decreases with increasing oxygen content in the films. The saturated magnetization shows a drastic increase and resistivity is significantly reduced in the ozone annealed samples, indicating the strong coupling between physical properties and oxygen content. These results demonstrate that the magnetic properties of PBCO films are highly dependent on the oxygen contents, or the film with higher oxygen uptake has the largest magnetization.