Origin of the long-wavelength magnetic modulation in ${\text{Ca}}_{3}{\text{Co}}_{2}{\text{O}}_{6}$

Origin of the long-wavelength magnetic modulation in ${Ca}_{3} {Co}_{2} O_{6}$

L. C. Chapon

Phys. Rev. B 80, 172405 – Published 23 November 2009

Abstract

The origin of the long-wavelength incommensurate magnetic structure of ${Ca}_{3} {Co}_{2} O_{6}$ is discussed considering possible interchains super-superexchange paths. The experimental value of the propagation vector $k = (0, 0, Δ)$ with $Δ > 1$ 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.