Theoretical analysis of the spin effect on the electronic and magnetic properties of the calcium manganese oxide CaMnO3: GGA+U calculation

An electron is a magnetic solid that can perturb local moment via exchange interactions between spin and those of the ions. In our paper, we explore the fundamental physics behind the scarcity of ferromagnetic coexistence on the calcium manganese perovskite oxide CaMnO3, and examine the structural, electronic and magnetic properties of some known magnetically ordered systems. Various magnetic structures are studied using the first-principles calculation based on density functional theory DFT, using different approximations such as local density approximation (LDA), generalized gradient approximation (GGA), LSDA+U, and GGA+U, which motivated our obtained results. We described in our paper the ground states of different magnetic phases: ferromagnetic (Ferro), A-type anti-ferromagnetic (A-AFM), and G-type anti-ferromagnetic (G-AFM), and the non-spin polarized (NSP) configuration for the ideal cubic perovskite structure. We investigated also a detailed study on the four-layered 4H-hexagonal structure of the compound. We have shown the band structure, density of states and the charge density of all configurations considered in our examination. The magnetic moment and the effect of the U-Hubbard term on our calculation are discussed. Our results are in excellent agreement with available theoretical works and experimental data. (C) 2010 Elsevier B.V. All rights reserved.