Research on new rare-earth half-metallic ferromagnets X0.75Eu0.25O (X=Ca, Sr and Ba) based on the first-principles calculations.

New rare-earth half-metallic ferromagnets X 0.75 Eu 0.25 O ( X =Ca, Sr and Ba) with the NaCl structure are predicted based on the first-principles calculations. These materials only have up-spin subbands at the Fermi level and their net magnetic moments are all 7.00 µ B per unit cell, which exhibits the evident half-metallic characteristics. Their energy gaps and half-metallic gaps are both wide so that they all have high Curie temperatures and stable half-metallicity, holding great potential applications in spintronics. From the calculated formation energies, it is possible to prepare Sr 0.75 Eu 0.25 O and Ba 0.75 Eu 0.25 O experimentally. However, it may be difficult to prepare Ca 0.75 Eu 0.25 O in experiments. The magnetic moments and the half-metallicity of X 0.75 Eu 0.25 O mainly originate from the spin-polarization of Eu 4f-orbitals, which are caused by the strong octahedral crystal field in the ligand compound ML 6 consisting of the Eu-ion and six O-ions around it. [ABSTRACT FROM AUTHOR]