Spin distribution and electronic structure of the ferromagnetic half-metal [Mn(bipy)(N3)2]: Ab initio study

Ab initio calculations have been performed to study the electronic structure and the alternating ferromagnetic-antiferromagnetic interactions of the manganese(II)-azido one-dimensional compound: [Mn(bipy)(N3)2] (bipy=2,2′-bipyridine). The density of states, the total energy and the spin magnetic moment were calculated. The calculations predict that the compound [Mn(bipy)(N3)2] is a ferromagnetic half-metal and the spin magnetic moment is 4.000μB per molecule. At the same time, it has a metallic antiferromagnetic metastable state. Based on the spin distribution obtained from ab initio calculations, we found that the spin populations are strongly positive on the Mn2+ ions. For the end-on (EO) azido groups, the magnetic moments are mainly distributed on the two terminal N1 and N3 atoms, weakly positive on the central N2 atoms. While for the end-to-end (EE) azido groups, the magnetic moments of the terminal N6 atoms are larger and that of the other terminal N4 atoms are smaller. The analysis of the spin populations shows that the ferromagnetic coupling through the azido groups is resulted from a spin delocalization mechanism together with the spin polarization effect. The results of our calculation are in good agreement with the experiment.