Half-metallic ferromagnetism in ordered LaBaCo₂O₆ and disordered La_0.5Ba_0.5CoO₃: DFT+U study

Ab-initio calculations are performed to investigate the magnetic structure of ordered LaBaCo₂O₆ and disordered La_0.5Ba_0.5CoO₃ systems using density functional theory (DFT). Structural relaxation by atomic force minimization and volume optimization are taken into account for both compounds. In confirmation with experimental data, ferromagnetic ordering is found energetically more favorable as compared to nonmagnetic and antiferromagnetic systems. For electronic properties, the calculations have been extended to treat the Co 3d states by self-interaction correction approach. We show that sufficiently high value of U yields the majority spin and minority spin channels, metallic and semiconductor respectively, making the systems half-metallic. The magnitude of Co magnetic moment is higher in ferromagnetic ordering than antiferromagnetic case, while a significant amount of moment is found on the O atoms. The iso-surface plots of ordered and disordered system exhibit that the charge on the Co atom is localized. - Highlights: • Magnetic properties of LaBaCo₂O₆ and La_0.5Ba_0.5CoO₃ are studied by using DFT. • Non-magnetic, ferromagnetic and anti-ferromagnetic orders are compared. • LaBaCo₂O₆ and La_0.5Ba_0.5CoO₃ are found to be half-metallic ferro-magnetic. • Ordered A site cation doping is found ideal for device applications