Ferromagnetic Cu₃N Nanoparticles Demonstrated by X-ray Magnetic Circular Dichroism (XMCD) and the Density Functional Theory (DFT) Calculations

In recent years, ferromagnetism induced by natural defects of nonmagnetic semiconductors has been widely investigated and expected to be applied in spintronics. On this basis, we report the ferromagnetic behavior of copper (I) nitride (Cu₃N) nanoparticles. A robust room temperature ferromagnetism is found in Cu₃N nanoparticles with the saturated magnetization of 4 memu/g (300 K). Based on the element-specific X-ray magnetic circular dichroism (XMCD) and the density functional theory (DFT) analysis, it is concluded that the ferromagnetism of Cu₃N nanoparticles originate from the surface Cu vacancies. Moreover, by increasing the surface area of Cu₃N, the variation of magnetism is realized, and the surface states related to ferromagnetism is further revealed.