Electronic structure and magnetic properties of an iron- and tantalum-based double perovskite

Abstract

Based on density functional theory, the dynamic stability, electronic structure, and magnetic properties of a LiNbO3 -type double perovskite (A2BB′O6), Zn2 FeTaO6, have been studied. Results show that the experimental structure is dynamic stabilized with a spontaneous polarization of ~57μCcm-2 along the c-axis. By using GGA+U method, the system is predicted to be a charge transfer type insulator with 4.3 μB magnetic moment on Fe ion. The easy axis is in the ab-plane. Calculations on exchange integrals indicate that the magnetic coupling between Fe ions of the Fe-O-Ta-O-Fe bridge is very weak. However, the AFM coupling of the Fe-O-Fe bridge is much stronger, which suggests a potential way to design magnetoelectric materials in ferrimagnetic phase with 3d and 5d ions at B- and B′-site in the LiNbO3 double perovskite system.