First-principles study of the effect of iron doping on the electronic and magnetic properties of TbMn2O5 Original Research Article

We have studied the electronic and magnetic properties of TbFexMn2−xO5 (x=0, 0.125, 0.25) samples using first-principles density functional theory within the generalized gradient approximation (GGA) schemes. The crystal structure of TbMn2O5 is orthorhombic containing Mn4+O6 octahedra and Mn3+O5 pyramids. The structure changes to monoclinic symmetry for the Fe-doping at the Mn sites. Our spin-polarized calculations give an insulating ground state for TbMn2O5 and a metallic ground state for Fe-doped TbMn2O5. Based on the magnetic properties calculations, it is found that the magnetic moment enhances with increase in the Fe-content in TbMn2O5. Most interestingly, the enhanced magnetic moment is due to a substantial reduction of the magnetic moments at the Fe sites.