Controlling the magnetic anisotropy of RuIr (m + n = 3) clusters using the MgO(001) substrate

Large perpendicular magnetic anisotropy energy (MAE) and flexible regulation of the magnitude and direction of MAE have great potential for application in information storage devices. Here, utilizing first-principles calculations, we investigated the magnetic properties of free and MgO(001) supported RuIr clusters (RuIr@MgO(m + n = 3)). The results indicate that the MAE of mixed clusters increases with the number of Ir atoms due to Ir having a strong coupling between the non-degenerate d and d_x states. The MAE of free Ir₃ is -8.18 meV with the easy magnetization direction parallel to the x-axis, while the MAE of supported Ir₃ on the MgO substrate increases by a factor of 2.6, and the easy magnetization axis of the structure is shifted to a direction perpendicular to the substrate surface. This change in MAE is due to the significant enhancement in the coupling between the non-degenerate d and d states near the Fermi level of Ir₃ atoms. Moreover, Ir₃@MgO possesses high thermodynamic stability. These results give a new method for manipulating MAE and the direction of easy magnetization, which has great potential for application in magnetic nanodevices.