Density Functional Theory Study of Oxygen Deficiencies in \(\textrm{SrCoO}_3\) Kevin Wilbert (a*), Abdul-Muizz Pradipto (b), and A. Agung Nugroho (b)
Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha No 10, Bandung 40132, Jawa Barat, Indonesia
Abstract
Strontium Cobaltite \(\textrm{SrCoO}_3\) is an oxide material that belongs to the perovskite class which exhibits interplays between spin, charge, and orbital degrees of freedom. The rich physical properties of \(\textrm{SrCoO}_3\) enable various potential applications such as magnetoresistance materials, ceramics membranes for oxygen separation, and cathode materials of solid oxide fuel cells. Recent reports indicate a possibility to manipulate the oxygen content of \(\textrm{SrCoO}_3\) by utilizing external perturbations such as external electric field or strain. Such modification will affect the electronic and magnetic properties of the material. In this study, the effects of oxygen deficiency from SrCoO3 are investigated using spin-polarized Density Functional Theory as implemented in the Full-potential Linearized Augmented Plane Wave (FLAPW) method, by explicit consideration of the correlation effects of the localized electrons in the Co 3d orbitals using the effective Hubbard \(U_{eff}\) parameter. The effective term is chosen to consist of the subtraction between the \(U\) value of 3 eV to denote the Coulomb interaction and the Hund^s coupling parameter \(J\) of 0.95 eV. Our results show that the localized character of the Co 3d orbitals is strongly changed by the modification of the oxygen content. The magnetic exchange interaction between two neighboring Co ions is therefore altered. As one of the consequences, the change of magnetic ground state is observed using the same \(U_{eff}\), where a ferromagnetic ordering is obtained on the full oxygen content, while \(\textrm{SrCoO}_{2.5}\) shows an antiferromagnetic behaviour.
