Possible non-collinear magnetic configurations in BaCoO3

The magnetic properties of BaCoO3 are strongly influenced by the frustration induced by the hexagonal structure. Previously, collinear configurations with ferromagnetically (FM) ordered hexagonal planes stacked antiferromagnetically (AF) along the c-axis (that of the Co chains) were found to be nearly degenerate and an orbitally ordered state (along c) was encountered. Here, we present a study of possible non-collinear magnetic structures in the system. We have used the WIEN2k software, which uses a full-potential, all-electron APW+lo (augmented plane waves plus local orbitals) method in a version adapted for studying non-collinear magnetic configurations. We explore this possibility of a non-collinear arrangement of the magnetic moments within the hexagonal plane, which could lead to a vanishing net magnetization within the plane. Due to the triangular arrangement of the Co chains and resulting frustrations, a simple AF order is not possible with any collinear configuration. Our calculations show that the most stable ordering is FM within the plane