Effect of Fe Doping on Magnetic Properties and Lattice Structure of Ferromagnetic EuO

The structural, electronic, and magnetic properties of Fe-doped EuO (Eu0.75Fe0.25O, Eu0.50Fe0.50O, and Eu0.25Fe0.75O) in the rock salt ferromagnetic phase have been studied. Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA) was used for structural analysis of these compounds. The lattice constant linearly decreased with increase in doping concentration of Fe atoms. Spin-polarized calculations were carried out using the modified Becke-Johnson exchange potential with Hubbard U correction (mBJ + U method). Semiconductor EuO showed a metallic character when doped with Fe atoms. The calculated density of states (DOS) of Eu0.75Fe0.25O, Eu0.50Fe0.50O, and Eu0.25Fe0.75O exhibit extra peaks of Fe atom 3 d states in the valance band between -10 and 3.5 eV. With an increase in Fe doping, the band gap was decreased due to an increase in spd exchange interaction between the band electrons and localized 3d electrons of transition atoms. Moreover, the properties of the doped EuO were found to be dependent on the location of dopant atoms.