Exchange coupling in Eu compounds

摘要

Using ab initio electronic structure calculations employing the LDA + U method we have investigated the exchange coupling in materials containing Eu in Eu2+ formal valency including: (i) insulating ferromagnets (EuO, EuS, EuSe, EuTe), and (ii) elemental metal BCC Eu. The total energies calculated with constrained magnetic structures were mapped on the Heisenberg Hamiltonian in order to investigate the thermodynamic properties. The mechanisms of inter-site exchange, which differ between the studied systems, are discussed. (c) 2005 Elsevier B.V. All rights reserved.