A stable 4f half-metallic ferromagnetism Eu4O3N predicted from GGA+U calculations

• Predicted half-metallic ferromagnet Eu4O3N with a half-metallic gap 0.376 eV and the large Eu ion magnetic moment up to about 7 μB.
• The Eu4O3N is structurally stable and magnetically robust.
• The Eu4O3N produce magnetism by virtue of f electrons.

   Objective: Half-metallic ferromagnetism plays a major role in high-performance spintronic applications due to its 100% spin-polarization. So, it is very necessary to search better half-metallic ferromagnets with large magnetic moment and being compatible with current semiconductor technology.Methods: We study cubic Eu4O3N on the basis of state-of-the-art first-principles calculations by using generalized gradient approximation plus U method.Results: It is found that the Eu4O3N is a half-metallic ferromagnet with a half-metallic gap of 376 meV and the large Eu ion magnetic moment up to about 7 μB. The structural and ferromagnetic stability are proved by mechanical stability criterion and magnetic energy differences, respectively. The half-metallic properties are also stable against the isotropic strain, volume-conservative tetragonal strain and rhombohedral distortion. For the choice of U between 4 and 8 eV, the Eu4O3N still is half-metallic ferromagnet.Conclusion: This provides a new idea for searching new half-metallic ferromagnetism by f electrons.Practical implications: If the Eu4O3N was experimentally synthesized with half-metallic properties, it should be used to design high-performance spintronic devices.