Perpendicular Magnetic Anisotropy and High Spin Polarization in Tetragonal Fe4N/BiFeO3 Heterostructures

The tetragonal Fe4N/BiFeO3 (001)heterostructures aimed at simultaneously gaining the perpendicular magnetic anisotropy (PMA) and high spin polarization have been investigated by the first-principles method. It is found that Fe4N with FeAFeB termination is better for achieving interfacial and inner PMA simultaneously than (Fe-B)(2)N termination. When the positions of interfacial Fe-A and Fe-B relative to Fe in BiFeO3 are changed, the PMA in Fe4N transforms into the in-plane magnetic anisotropy. Especially, PMA in Fe4N near the heterointerfaces depends on the direction of ferroelectric polarization in BiFeO3. Finally, the interfacial and inner PMA of Fe4N along with high spin polarization appear in the stable FeAFeB/Fe-O-2 case owing to the 3d-3d orbital hybridization. These results provide the opportunities for developing multifunctional spintronic devices.