Magnetic map of Cr adatom, Cr dimer and Cr–O on Co(0001) hcp: first principles calculations

Magnetism of Cr adatom, Cr dimer and Cr–O on Co(0001) hcp substrate is studied on the basis of density functional theory using Quantum Espresso code. The most stable geometry occurs when Cr is adsorbed in the most highly coordinated sites. Cr adatom couples antiferromagnetically with the Co atoms and shows a high magnetic moment of 4.57 \(\mu _B\). Cr dimer also couples antiferromagnetically with the Co atoms, shows a magnetic moment of 4.50 \(\mu _B\) for both Cr atoms and increases its interatomic distance to minimize its energy. For the Cr–O, the most stable state is when the Cr atom is coupled antiferromagnetically with Co substrate atoms. The effect of O atom decreases the Cr and Co atomic magnetic moments for the first nearest neighbors. For Cr–O, calculations were performed with DFT and DFT+U approaches because oxygen is not well described by DFT-only. The DFT+U increases the interatomic distances and magnetic moments on Cr and its Co nearest neighbors.