Manipulation of magnetic anisotropy in Irn+1 clusters by Co atom

• The Ir2, Ir4, and CoIr system possess large magnetic anisotropy energy (MAE).
• The MAE of Irn+1 cluster can be manipulated by Co atom.
• Such tunable MAE is ascribed to the change in the distribution of Ir-5d orbitals.

Based on the first principles calculations, we have investigated the magnetic properties of Irn+1 clusters modulated by Co atoms. The research conclusions show that the amplitude of magnetic anisotropy energy (MAE) and magnetization direction of the small Irn+1 can be manipulated by Co atom if we can control the size very precisely. Such regulatory mechanism of MAE is ascribed to the distributing variation of Ir-5d orbits around the Fermi level induced by Co atom. More importantly, the colossal MAE values, 67.4 meV/atom, 40.26 meV/atom and 91.37 meV/atom, can be obtained for Ir2, Ir4, and CoIr clusters, respectively. Such high values provide a promising avenue for developing high-density magnetic storage units at sub-nanometer size.