High-efficiency spin filtering in salophen-based molecular junctions modulated with different transition metal atoms

•The spin transport properties in salophen-based magnetic molecular junctions.•Perfect spin filtering behavior is observed in only Co-salophen junction.•The conductance through Co-salophen junction is dominated by spin-down electrons.

Based on the density functional theory and nonequilibrium Green's function methods, we investigate the spin transport properties of the molecular junctions constructed by a homologous series of 3d transition metal(II) salophens (TM-salophens, TM = Co, Fe, Ni and Mn) sandwiched between two gold electrodes. It is found that among the four molecular junctions only Co-salophen junction can act as an efficient spin filter distinctively. The conductance through Co-salophen molecular junction is dominated by spin-down electrons. The mechanism is proposed for these phenomena.