Effects of copper and oxygen vacancies on the ferromagnetism of Mn- and Co-doped Cu2O

The ferromagnetic properties of Mn- and Co-doped Cu2O with copper and oxygen vacancies (VCu and VO) are studied by first-principles calculations. The results indicate that Mn-doped Cu2O has an antiferromagnetic state in the near configuration, while it has a ferromagnetic state for the far configuration. On the contrary, Co-doped Cu2O possess a ferromagnetic state regardless of the distance between the two Co atoms. The observed ferromagnetism can be attributed to the 90° ferromagnetic super-exchange mechanism. The presence of VO can enhance the ferromagnetism, whereas VCudepresses it.