First-principles investigation on multiferroic properties of BiFeO3-REMnO3 (RE = Er, Eu, Gd, Ho, La, Tb)

Structural and multiferroic properties of BiFeO3-REMnO3 solid solution (RE = Er, Eu, Gd, Ho, La, Tb) have been investigated using the first-principle calculations. Simultaneous substitution of Gd and Mn in BiFeO3 of 12.5% has been carried out. We found that the total magnetic moment in BiFeO3-REMnO3 is decisively governed by the magnetic moments of rare-earth elements. Our calculations achieved a total magnetic moment of 3.58, 4.69, 5.8, 4.27, 1.5 and 6.31 mu(B) in BiFeO3-REMnO3 for RE = Er, Eu, Gd, Ho, La and Tb, respectively. The calculated total densities of states for all studied materials are clearly asymmetrical with metal characteristics. Further, a pseudo Jahn-Teller distortion was predicted for BiFeO3-GdMnO3 with the changes in the octahedral tilting angle theta which is responsible for higher magnetization in this system. The spontaneous polarization of BiFeO3-REMnO3 systems was determined by berry phase methods. The obtained results are close to the experimental and other theoretical results.