Gold-Coated Transition-Metal Anion [Mn₁₃@Au₂₀]^- with Ultrahigh Magnetic Moment

Structures and magnetic properties of gold-coated transition-metal clusters [Mn₁₃@Au₂₀]^- and [Co₁₃@Au₂₀]^- are studied within the framework of gradient-corrected density functional theory. The gold coating can result in either an enhanced or an attenuated effect on the magnetism of the core clusters. For [Mn₁₃@Au₂₀]^-, the total magnetic moment is greatly enhanced to as high as 44 μ_B, more than 20-fold higher than that of the bare Mn₁₃^- cluster. For [Co₁₃@Au₂₀]^-, however, the gold coating gives rise to an attenuation effect which leads to a reduction of the magnetic moment to 20μ_B from 30μ_B of the bare Co₁₃^- cluster.