Structures, stabilities, and magnetic properties of the Fe_nAu (n= 1-12) clusters

The configurations, stabilities, electronic, and magnetic properties of Fe_nAu (n= 1-12) clusters are investigated systematically by using the relativistic all-electron density functional theory with the generalized gradient approximation. The substitutional effects of Au in Fe_n+1 (n= 1, 2, 4, 5, 10-12) clusters are found in optimized structures which keep the similar frameworks with the most stable Fe_n+1 clusters. And the growth way for Fe_nAu (n= 6-9) clusters is that the Au atom occupies a peripheral position of Fe_n cluster. The peaks appear respectively at n= 6 and 9 for Fe_nAu clusters and at n= 5 and 10 for Fe_n+1 clusters based on the size dependence of second-order difference of energy, implying that these clusters possess relatively high stabilities. The analysis of atomic net charge Q indicates that the charge always transfers from Fe to Au atom which causes the Au atom to be nearly non-magnetic, and the doped Au atom has little effect on the average magnetic moment of Fe atoms in Fe_nAu cluster. Finally, the total magnetic moment is reduced by 3 μ_B for each of Fe_nAu clusters except n= 3, 11, and 12 compared with for corresponding pure Fe_n+1 clusters.