Magnetism and optical properties of LiNbO3 doped with (Fe,Ni,Ga): First-principles calculations

Based on the first principles of the generalized gradient approximation method, the magnetic and optical properties of Fe-, Ni-doped and (Fe,Ni) co-doped LiNbO 3 crystals are studied. The results show that the mono-doped LiNbO 3 crystals contain magnetic atoms (Fe,Ni) leading to spin polarization, and (Fe,Ni) co-doped LiNbO 3 crystals tend to the ferromagnetic state with △EFM of −143 meV. The total magnetic moment of the (Fe,Ni) co-doped LiNbO 3 crystal is 5.97  μB, and the local magnetic moments of Fe and Ni are 2.99  μB and 0.93  μB, respectively. It is interesting that the introduction of the Ga atom makes the ferromagnetic state ( △EFM of −285.4 meV) of the (Fe,Ni) co-doped LiNbO 3 system more stable than the anti-ferromagnetic state. Although Ga atoms do not contribute to the magnetic moment, the (Fe,Ni,Ga) co-doped LiNbO 3 is more conducive to the spin-polarized state. In addition, with the introduction of Fe, Ni, and Ga atoms, the visible region absorption changes significantly. Non-volatile holographic storage can be achieved by (Fe,Ni) co-doped LiNbO 3, thus increasing the absorption of the visible light range. In summary, this research provides theoretical guidance for the application of LiNbO 3 crystals in spintronic devices.