Electronic and magnetic properties of new half-metallic ferromagnetic rutile Ti1-x-yVxNiyO2 (x = y = 6.25%): A first-principles study

We report electronic and magnetic properties of the new half-metallic ferromagnetic co-doped system of rutile Ti1-x-yVxNiyO2 (x = y = 6.25%). The semiconductor ferromagnetic doped system of rutile Ti1-xVxO2 (x = 6.25%) system is revisited as the reference. The plane-wave GGA + U method was used after choosing U at Ti 3d site in the fully-optimized rutile TiO2. The co-doped system exhibits the total magnetic moment of 1.41 μB/Ni atom localized at the V and Ni sites which is significantly higher than that of the doped system. Interestingly, the local ferrimagnetism centered at the cations of V4+ and Ni3+ is found with the minor contribution from their nearest-neighboring O2− ions bound via the p-d hybridization. The Ni3+ ion induces the half-metallic behavior by introducing spin-up hole O 2p states above the Fermi energy level. Finally, the GGA + U provides accurate energy positions of sub-V 3d and Ni 3d states under the elongation Jahn-Teller distortion at the VO6 and NiO6 octahedra. Our result shows the significant effect of Ni3+ ion in modifying the electronic and magnetic properties of the rutile Ti1-xVxO2 system. This study presents the essentials properties which can be a guide for experiments.