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

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 Eu 4 O 3 N 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 Eu 4 O 3 N is a half-metallic ferromagnet with a half-metallic gap of 376 meV and the large Eu ion magnetic moment up to about 7 μ B . 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 Eu 4 O 3 N still is half-metallic ferromagnet. Conclusion : This provides a new idea for searching new half-metallic ferromagnetism by f electrons. Practical implications : If the Eu 4 O 3 N was experimentally synthesized with half-metallic properties, it should be used to design high-performance spintronic devices. [ABSTRACT FROM AUTHOR]