A Theory of Magnets with Competing Double Exchange and Superexchange Interactions
arXiv:cond-mat/9712094 · doi:10.1063/1.367798
Abstract
We study the competition between ferromagnetic double exchange (DE) and nearest-neighbour antiferromagnetic exchange in CMR materials. Towards this end, a single site mean field theory is proposed which emphasizes the hopping-mediated nature of the DE contribution. We find that the competition between these two exchange interactions leads to ferro- or antiferromagnetic order with incomplete saturation of the (sub)lattice magnetization. This conclusion is in contrast to previous results in the literature which find a canted spin arrangement under similar circumstances. We attribute this difference to the highly anisotropic exchange interactions used elsewhere. The associated experimental implications are discussed.
4 pages, Latex-Revtex, 3 PostScript figures. Please see report cond-mat/9805238