Enhanced stability and ferromagnetic property in transition metals co-doped rutile TiO2

Stability and magnetic property analysis have been done for 3d transition metal doped rutile TiO2 using density functional theory. Applying spin polarized density of states calculation and spin-spin interaction study wherever possible, it has been seen that among all the 3d transition metal dopants only Fe doping can induce ferromagnetism in the TiO2 system. Anti-ferromagnetic spin ordering has been seen for Mn and Cu doped rutile TiO2. Though Mo is not a 3d transition metal but is from the next series and shows favorable ferromagnetic spin ordering. For the purpose of increasing the ferromagnetic ordering in the systems, co-doping studies have been performed for Cu-Mn, Cu-Fe and Fe-Mo co-doped systems. For the above three co-doped systems, it has been seen that even those elements whose solo-doping shows anti-ferromagnetic ordering (Mn, Cu) can generate long range cooperative type ferromagnetic ordering after co-doping. So co-doping can be used as an interesting and useful tool to increase ferromagnetic ordering of diluted magnetic semiconductor oxide systems.