Small FenMn clusters: Magnetic order and magnetic moment

The effects of a manganese atom on the magnetic order and magnetic moments of FenMn (n=1–12n=1–12) clusters have been investigated using the all-electron density functional theory. The results reveal that the Fe–Mn couplings in the lowest-energy structures of FenMn (n=1–12n=1–12) clusters undergo a change from ferromagnetic ordering for the smallest (n=1,2n=1,2) clusters to ferrimagnetic ordering for the intermediate (n=3–6n=3–6) clusters. Starting from n=7n=7, however, ferromagnetic Fe–Mn couplings completely prevail. The low coordination number of the doped Mn atom results in it having a high spin moment in the Fe–Mn binary clusters, which exhibits a marked magnetic moment surface enhancement effect.