A new half-metallic ferromagnet La2NiFeO6: Predicted from first-principles calculations

Electronic structure calculations based on density functional theory in both optimized monoclinic (No. 14 P2(1)/n) and rhombohedral (No. 148 R (3) over bar) phases of La2NiFeO6 have been performed using full-potential linearized augmented plane wave method. The result indicates that La2NiFeO6 is a half-metallic ferromagnet within both crystal structures, and electronic correlation (U) plays a vital role in stabilizing the ferromagnetic ground state. Substitution of Mn4+ with Fe3+ induces a hole on Ni, making the transition of semiconducting La2Ni2+Mn4+O6 to half-metallic La2Ni3+Fe3+O6. Moreover, the half-metallicity is found to be robust under the compressive and tensile strains for both phases. The magnetic interaction constant is calculated according to the Heisenberg model, from which the Curie temperature is estimated within the mean field approximation. The Curie temperature is predicted to be as large as 495 and 474 K in P2(1)/n and R (3) over bar, respectively, making this system interesting candidates in spintronic devices.