Frustrated network of indirect exchange paths between tetrahedrally coordinated Co in Ba2CoO4

TL;DR

This study investigates the electronic and magnetic properties of Ba2CoO4, revealing a complex 3D magnetic network with frustration, primarily mediated by oxygen atoms through indirect exchange pathways.

Contribution

It provides a detailed analysis of the magnetic interactions in Ba2CoO4, highlighting the role of oxygen-mediated indirect exchange in a structurally uncommon tetrahedral cobalt environment.

Findings

Presence of spin-polarized oxygen atoms with magnetic moments parallel to Co.

Identification of a 3D network of magnetic couplings with partial frustration.

Dominance of oxygen-mediated indirect exchange in the magnetic ground state.

Abstract

We present a detailed study of the electronic and magnetic interactions of Ba2CoO4, structurally very uncommon because of the isolated CoO4 distorted tetrahedral coordination. We show the presence of Co(d)-O(p) hybridized states characterized by spin polarized oxygen atoms, with their magnetic moments parallel to that on Co. The calculated isotropic exchange interaction parameters, which include the contributions from ligand spins, demonstrate the presence of a 3D network of magnetic couplings, that are partially frustrated in the identified magnetic ground state. Our results indicate that the dominant indirect exchange mechanism responsible for this ground state is mediated by O atoms along the Co-O...O-Co path.