材料期刊网

First principles calculations have been performed to study the electronic structure and the ferromagnetic properties on the two chain compounds of [M(N-3)(2) (HCOO)] [(CH3)(2)NH2] (M = Fe and Co). The relative stability of the ground state, the density of states and the electronic band structure are examined. The results reveal that antiferromagnetism (AFM) state is the ground state and ferromagnetism (FM) state is the metastable one for both of them. The two compounds exhibit semiconductor character with small gap in the FM state, while metallic in the AFM state. In the FM state, the magnetic moments mainly arise from the Fe and Co ions with little contribution from the nearest-neighboring N and O atoms due to the hybridization between the Fe or Co 3d states and the nearest-neighboring N and O 2p states. (C) 2007 Elsevier Ltd. All rights reserved.