Origin of the long-wavelength magnetic modulation in Ca3Co2O6

TL;DR

This paper investigates the origin of the long-wavelength magnetic modulation in Ca3Co2O6, revealing that next nearest super-superexchange interactions are crucial for explaining the incommensurate magnetic structure.

Contribution

It demonstrates that considering next nearest super-superexchange interactions explains the incommensurate magnetic structure in Ca3Co2O6, supported by a spin-dimer analysis.

Findings

Next nearest super-superexchange interactions are essential.

The extended-Huckel Tight-Binding method confirms strong longer-range interactions.

The observed magnetic structure's stability is analyzed.

Abstract

The origin of the long-wavelength incommensurate magnetic structure of Ca3Co2O6 is discussed considering possible inter-chains super-superexchange paths. The experimental value of the propagation vector k=(0,0,$\Delta$) with $\Delta$ $>$ 1 can be reproduced only if one considers the next nearest super-superexchange interaction. A spin-dimer analysis using the Extended-Huckel Tight-Binding method confirms that, despite longer interatomic Co-Co distances, the latter interaction is indeed much stronger. The stability of the observed structure with respect to certain commensurate states is discussed.