Fluorite-type phase of TiO2 (co)-doped with (Co, Nb and Ru): first-principles calculations

In this work, the effect of cobalt, niobium and ruthenium, as single and double impurities, on the structural, magnetic and electronic properties of titanium dioxide ( $${\mathrm{TiO}}₂$$ ) is investigated on the basis of the Korringa Kohn Rostoker (KKR) method in combination with the coherent potential approximation (CPA). The exchange-correlation term is addressed within the generalized gradient approximation (GGA). The densities of states demonstrate a clear development of half-metallic (HM) behaviour with high spin polarization at the Fermi level (up to 100%) for the case of doping with cobalt. Furthermore, co-doping (Nb, Ru) increases the Curie temperature of $${\mathrm{TiO}}₂$$ to the maximum values of 542 and 440 K reached for Nb and Ru co-doped $${\mathrm{TiCoO}}₂$$ , respectively. In these compounds, the super-exchange and double-exchange interaction mechanisms explain the stability of ferromagnetic (FM) and anti-ferromagnetic (AFM) orders. Our findings confirm that these new materials have an enhanced potential for spintronic devices.