The direct exchange interaction for weakly delocalized multielectron systems in crystals

• Published in: Journal of magnetism and magnetic materials 1977-01, Vol.5 (1), p.1-8
• Main Authors: Sidorov, A.A., Gubanov, V.A.
• Format: Article
• Language: English
• ISSN: 0304-8853
• DOI: 10.1016/0304-8853(77)90190-1

The multielectron theory of exchange interactions taking into account both electrostatic interactions between electrons (“potential” exchange) and electron transfer between magnetic centers (“kinetic” exchange) has been developed on the basis of Bogolubov's procedure using double irreducible operators. The final hamiltonian contains a number of isotropic and anisotropic terms. The exchange interaction parameter variations with the distance have been calculated. The terms determining the dependence on the occupancy of magnetic shells are shown to be of the same order of magnitude as the “potential” exchange and two orders of magnitude less than the “kinetic” exchange. It is shown that in the model adopted the mechanisms of direct exchange interactions always favour the antiferromagnetic spin ordering